Windows 7

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Tips and Tricks

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How To(s)

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Downloads

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Wallpapers

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Quote of the Day

Sunday, February 28, 2010

The Power of One


The Power of One


























































Saturday, February 27, 2010

19 Free Ways Download Videos from the Net

19 Free Ways Download Videos from the Net 

It seems like everyone these days is downloading, watching, and sharing videos from video-sharing sites like YouTube, Google Video, MetaCafe, DailyMotion, Veoh, Break, and a ton of other similar sites. Whether you want to watch the video on your iPod while working out, insert it into a PowerPoint presentation to add some spice, or simply download a video before it’s removed, it’s quite essential to know how to download, convert, and play these videos.

There are basically two ways to download videos off the Internet and that’s how I’ll split up this post: either via a web app or via a desktop application. Personally, I like the web applications better simply because you don’t have to clutter up and slow down your computer with all kinds of software!
Free Web services for downloading videos from video-sharing sites:
Zamzar is a free online file conversion web application that can not only convert videos off the Internet to AVI, MPEG, 3GP, MP4, MOV, etc, but also converts between audio, image, and document formats. Paste the URL into Step 1 and then convert the file to your favorite format.
ClipNabber allows you to download videos from YouTube, Metacafe, etc by simply copying and pasting the URL. You’ll then get a link whereby you can download the file to your computer, iPod, iPhone, or any other media player. You’ll need to have an FLV player for the YouTube videos. Quick and very easy to use!

VideoDownloader is a FireFox extension, but also allows you to paste in any URL from many sites such as Blip.TV, iFilm, and even social networking sites like MySpace. You can also download a free FLV player from their site to play the videos.

Vixy.net is another site that not only downloads online videos, but will also convert them AVI, MOV, MP4, 3GP, or MP3 (if you want to extract the audio from the file). Using this site, you don’t have to worry about downloading a FLV player as you can convert it to Windows format. (Same as Zamzar)

KeepVid also supports just about any video sharing site out there and the only difference about this site is that it also has a Top Videos section, so you can quickly download the most watched videos around the web.

Media Converter is similar to ZamZar and vixy.net, but requires you to create an account and log in. Also, it seems like it only supports downloading and converting videos from YouTube. You can also download their video download program, but it only supports 5 sites.

Hey! Watch is an online video encoding web service that encodes video into different formats including HD very quickly. The graphical interface is very nice and there are lots of features and options, such as the ability to transfer any video from the web directly to an FTP server or toonline storage.

YoutubeX, as the name suggests, allows you to download videos from YouTube. Obviously, it only supports YouTube, but it has a couple of other features, such as the ability to play your video on the site and find popular videos quickly.

VideoRonk searches across multiple video-sharing sites such as Google Video, YouTube, MetaCafe and DailyMotion to find the most popular videos on each of them. You can either watch them on VideoRonk or download them to your computer in FLV format.

VidDownloader supports about 10 sites including the major ones and can download the videos in DivX AVI format. It’s very easy to use and can also extract only the audio from a video by choosing “Just Audio” on the download page. You don’t have to worry about having an FLV playersince it converts the files to Windows format.

According to their web site, they support more than 98 video sites including MySpace, CollegeHumor, iFilm, etc. You’ll have to rename the files you download from YouTube with the .FLV extension at the end.

This site is a foreign site, but is easy to use and supports most of the major sites. You can also download a free FLV player off their site to play videos from YouTube.


DownThisVideo has a nice tag cloud at the top that you can click on to find videos quickly. From what I could tell, this site is mostly used by Japanese because the popular videos are mostly Anime, etc. However, you can still use it to download any YouTube video.

Video Downloaders for your DeSktop:

If you prefer to have a desktop application that can download videos for you, check out the following list:

1. Orbit Downloader - This is by far the best desktop application I have seen for downloading any type of social media off the Internet. It can download videos and music from MySpace, YouTube, Pandora, Rapidshare, and lots more. It has a great interface and carries a very small foot print.

2. VDownloader - A small little application that can download videos from many sites and converts them to AVI or MPG format.

3. VideoDownloader - A useful FireFox add-on that supports more than 60 video sharing sites. It can also download other objects on a web page, such as movies, MP3s, flash files, and Quicktime movies directly.

4. Ares Tube - Another popular video download application that is very small and very easy to use. You can download videos in batches by entering URLs into a queue and Ares Tube can convert them into different formats such as iPod, MP4, MPG, etc.

5. YouTubeGrabber - Not a very fancy program, it simply takes your URL and downloads the file. No conversion is done and you’ll need to install an FLV player to watch the videos.

6. KeepV - Downloads videos from YouTube, MySpace, and Google and converts them to either MOV, 3GP, AVI, iPod, or PSP format.

Hopefully, using one of the tools above, you can download the video you want! I’m sure the arsenal of web services and desktop apps will grow, so this list will be updated as needed.

Speed-up your Acrobat Reader

Speed-up your Acrobat Reader 

Do u get irritated when acrobat reader takes 5/10 seconds to load when you want to open a pdf document. There is a way to speed up the loading.
Here is how you can do it ---

1. Go to the installation folder of acrobat reader (C:\program files\adobe\acrobat\reader\.. whatever)
2. Move all the files and folders from the "plugins" directory to the "Optional" directory. (I repeat.. cut and paste the files NOT copy & paste). Also make sure that acrobat reader is not open else it will lock the files and not allow you to move the files).

Now your acrobat reader will load very fast and almost as good as notepad..

Friday, February 26, 2010

Download Any Video From Any Site

Download Any Video From Any Site

There are many videos on the Intenet. Some are protected and other videos don’t provide you with any download link. It screams for a need of a hack, to download videos from any site. It’s one of the easiest hack on the web. You can make it more simple if you are have a Firefox browser installed on your PC. If you don’t have Firefox, Download one from Here. It’s the world’s most used web browser




Now you have Firefox installed on your PC. Now open the browser and download the NetvideoHunter add-on to your browser. You can download it from Here. With this add-on, you can easily download videos and music from almost any video-sharing site.

For example from: Youtube, MySpace Music, Google Video, Metacafe, Dailymotion, Break, Putfile, etc…

Before download ,you can preview videos and music in a built-in media player. It has fullscreen and video smoothing capabilities, so you can enjoy videos in fullscreen with better quality even if the website’s own player don’t have this features.

Now every videos you see is just a click away from here.You can download any videos just with a click on your browser. Why you are waiting – Install this add-on and Be The KI
NG !!!



Download the NetVideoHunter

All XP Commands

All XP Commands

Run Commands:

compmgmt.msc - Computer management
devmgmt.msc - Device manager
diskmgmt.msc - Disk management
dfrg.msc - Disk defrag
eventvwr.msc - Event viewer
fsmgmt.msc - Shared folders
gpedit.msc - Group policies
lusrmgr.msc - Local users and groups
perfmon.msc - Performance monitor
rsop.msc - Resultant set of policies
secpol.msc - Local security settings
services.msc - Various Services
msconfig - System Configuration Utility
regedit - Registry Editor
msinfo32 _ System Information
sysedit _ System Edit
win.ini - windows loading information(also system.ini)
winver - Shows current version of windows
mailto Opens default email client
command - Opens command prompt

Run Commands to access the control panel:

appwiz.cpl -Add/Remove Programs control
timedate.cpl -Date/Time Properties control
desk.cpl -Display Properties control
findfast.cpl -FindFast control
inetcpl.cpl -Internet Properties control
main.cpl keyboard -Keyboard Properties control
main.cpl -Mouse Properties control
mmsys.cpl -Multimedia Properties control
netcpl.cpl -Network Properties control
password.cpl -Password Properties control
mmsys.cpl sounds -Sound Properties control
sysdm.cpl -System Properties control

Command Prompt:

ANSI.SYS Defines functions that change display graphics, control cursor movement, and reassign keys.
APPEND Causes MS-DOS to look in other directories when editing a file or running a command.
ARP Displays, adds, and removes arp information from network devices.
ASSIGN Assign a drive letter to an alternate letter.
ASSOC View the file associations.
AT Schedule a time to execute commands or programs.
ATMADM Lists connections and addresses seen by Windows ATM call manager.
ATTRIB Display and change file attributes.
BATCH Recovery console command that executes a series of commands in a file.
BOOTCFG Recovery console command that allows a user to view, modify, and rebuild the boot.ini
BREAK Enable / disable CTRL + C feature.
CACLS View and modify file ACL's.
CALL Calls a batch file from another batch file.
CD Changes directories.
CHCP Supplement the International keyboard and character set information.
CHDIR Changes directories.
CHKDSK Check the hard disk drive running FAT for errors.
CHKNTFS Check the hard disk drive running NTFS for errors.
CHOICE Specify a listing of multiple options within a batch file.
CLS Clears the screen.
CMD Opens the command interpreter.
COLOR Easily change the foreground and background color of the MS-DOS window.
COMP Compares files.
COMPACT Compresses and uncompress files.
CONTROL Open control panel icons from the MS-DOS prompt.
CONVERT Convert FAT to NTFS.
COPY Copy one or more files to an alternate location.
CTTY Change the computers input/output devices.
DATE View or change the systems date.
DEBUG Debug utility to create assembly programs to modify hardware settings.
DEFRAG Re-arrange the hard disk drive to help with loading programs.
DEL Deletes one or more files.
DELETE Recovery console command that deletes a file.
DELTREE Deletes one or more files and/or directories.
DIR List the contents of one or more directory.
DISABLE Recovery console command that disables Windows system services or drivers.
DISKCOMP Compare a disk with another disk.
DISKCOPY Copy the contents of one disk and place them on another disk.
DOSKEY Command to view and execute commands that have been run in the past.
DOSSHELL A GUI to help with early MS-DOS users.
DRIVPARM Enables overwrite of original device drivers.
ECHO Displays messages and enables and disables echo.
EDIT View and edit files.
EDLIN View and edit files.
EMM386 Load extended Memory Manager.
ENABLE Recovery console command to enable a disable service or driver.
ENDLOCAL Stops the localization of the environment changes enabled by the setlocal command.
ERASE Erase files from computer.
EXIT Exit from the command interpreter.
EXPAND Expand a M*cros*ft Windows file back to it's original format.
EXTRACT Extract files from the M*cros*ft Windows cabinets.
FASTHELP Displays a listing of MS-DOS commands and information about them.
FC Compare files.
FDISK Utility used to create partitions on the hard disk drive.
FIND Search for text within a file.
FINDSTR Searches for a string of text within a file.
FIXBOOT Writes a new boot sector.
FIXMBR Writes a new boot record to a disk drive.
FOR Boolean used in batch files.
FORMAT Command to erase and prepare a disk drive.
FTP Command to connect and operate on a FTP server.
FTYPE Displays or modifies file types used in file extension associations.
GOTO Moves a batch file to a specific label or location.
GRAFTABL Show extended characters in graphics mode.
HELP Display a listing of commands and brief explanation.
IF Allows for batch files to perform conditional processing.
IFSHLP.SYS 32-bit file manager.
IPCONFIG Network command to view network adapter settings and assigned values.
KEYB Change layout of keyboard.
LABEL Change the label of a disk drive.
LH Load a device driver in to high memory.
LISTSVC Recovery console command that displays the services and drivers.
LOADFIX Load a program above the first 64k.
LOADHIGH Load a device driver in to high memory.
LOCK Lock the hard disk drive.
LOGON Recovery console command to list installations and enable administrator login.
MAP Displays the device name of a drive.
MD Command to create a new directory.
MEM Display memory on system.
MKDIR Command to create a new directory.
MODE Modify the port or display settings.
MORE Display one page at a time.
MOVE Move one or more files from one directory to another directory.
MSAV Early M*cros*ft Virus scanner.
MSD Diagnostics utility.
MSCDEX Utility used to load and provide access to the CD-ROM.
NBTSTAT Displays protocol statistics and current TCP/IP connections using NBT
NET Update, fix, or view the network or network settings
NETSH Configure dynamic and static network information from MS-DOS.
NETSTAT Display the TCP/IP network protocol statistics and information.
NLSFUNC Load country specific information.
NSLOOKUP Look up an IP address of a domain or host on a network.
PATH View and modify the computers path location.
PATHPING View and locate locations of network latency.
PAUSE Command used in batch files to stop the processing of a command.
PING Test / send information to another network computer or network device.
POPD Changes to the directory or network path stored by the pushd command.
POWER Conserve power with computer portables.
PRINT Prints data to a printer port.
PROMPT View and change the MS-DOS prompt.
PUSHD Stores a directory or network path in memory so it can be returned to at any time.
QBASIC Open the QBasic.
RD Removes an empty directory.
REN Renames a file or directory.
RENAME Renames a file or directory.
RMDIR Removes an empty directory.
ROUTE View and configure windows network route tables.
RUNAS Enables a user to execute a program on another computer.
SCANDISK Run the scandisk utility.
SCANREG Scan registry and recover registry from errors.
SET Change one variable or string to another.
SETLOCAL Enables local environments to be changed without affecting anything else.
SETVER Change MS-DOS version to trick older MS-DOS programs.
SHARE Installs support for file sharing and locking capabilities.
SHIFT Changes the position of replaceable parameters in a batch program.
SHUTDOWN Shutdown the computer from the MS-DOS prompt.
SMARTDRV Create a disk cache in conventional memory or extended memory.
SORT Sorts the input and displays the output to the screen.
START Start a separate window in Windows from the MS-DOS prompt.
SUBST Substitute a folder on your computer for another drive letter.
SWITCHES Remove add functions from MS-DOS.
SYS Transfer system files to disk drive.
TELNET Telnet to another computer / device from the prompt.
TIME View or modify the system time.
TITLE Change the title of their MS-DOS window.
TRACERT Visually view a network packets route across a network.
TREE View a visual tree of the hard disk drive.
TYPE Display the contents of a file.
UNDELETE Undelete a file that has been deleted.
UNFORMAT Unformat a hard disk drive.
UNLOCK Unlock a disk drive.
VER Display the version information.
VERIFY Enables or disables the feature to determine if files have been written properly.
VOL Displays the volume information about the designated drive.
XCOPY Copy multiple files, directories, and/or drives from one location to another.
TRUENAME When placed before a file, will display the whole directory in which it exists
TASKKILL It allows you to kill those unneeded or locked up applications

Hewlett-Packard computers are racist


'Hewlett-Packard computers are racist' 

Published on Wed 23rd Dec 2009 13:10:46

Melbourne, Dec 23: Software giant Hewlett-Packard (HP) has admitted that its new face-tracking webcam has "issues" with black users.

The issue attracted worldwide attention this month, when a US man known as "Black Desi" posted a YouTube video that showed his HP webcam - built in to its new computers - refusing to track his face.

According to news.com.au, the webcam was developed to enhance live conversations and is supposed to follow the user in all directions and zoom in and out.

Titled "HP computers are racist", the YouTube video quickly attracted some 500,000 hits and showed Black Desi''s webcam working as it should when his work colleague "White Wanda" stepped in front of the camera, but when “Black Desi” got in front, no face recognition took place.

The video, which was part tongue-in-cheek, has sparked worldwide debate in the online community, with websites and forums split between discrediting the clip - claiming it''s a lighting issue - or attacking HP for "inherent racism".

In Case you wanna see the video I am talking about. Here it is : 


and HP's response:

For the backstory, watch this video that shows how HP’s new webcams discriminate against those with dark skin. Interesting, eh? HP no doubt got a bunch of emails over the last couple days and issued a response that basically says it was caused by the algorithm not properly measuring the light between the eyes and upper cheek. HP’s solution: “try to increase the light to the face while decreasing the amount of light in the background.”




Help India at War


Help India at War

In an online war against various big countries in new world of erepublik India is trying hard to survive. Right now India is in war against Iran and Pakistan. No wonder Pakistan again betrayed us and helping Iran to wipe of India from world map.


www.erepublik.com is the new world on internet where you can be a soldier for you country. You can be a massive army tank, an army general, a business tycoon or even you can join politics and be a president of country. Control virtual life of real people, make friends, allies, business empires or special elite fighting groups. 

If you are good in writing and reading you can be Media Mogul as well. Start a newspaper in game and see world audience following you and praising you.

As of now India's situation is DO or DIE. We are dieing slowly. 

We don't have strong population to support us in new world. However India got a very high number online gamers and people who use internet. If you love your country, if you want to help India. Join Strategy Game Free Online Multiplayer Strategy Games | eRepublik in India in Maharashtra.

Top 10 Hackers of all Time


Top 10 Hackers of all Time

1983
Kevin Poulsen again. A little-known incident when Poulsen, then just a student, hacked into Arpanet, the precursor to the Internet was hacked into. Arpanet was a global network of computers, and Poulsen took advantage of a loophole in its architecture to gain temporary control of the US-wide network.

1988
Twenty-three-year-old Cornell University graduate Robert Morris unleashed the first Internet worm on to the world. Morris released 99 lines of code to the internet as an experiment, but realised that his program infected machines as it went along. Computers crashed across the US and elsewhere. He was arrested and sentenced in 1990.

Early 1990s
Kevin Mitnick, often incorrectly called by many as god of hackers, broke into the computer systems of the world's top technology and telecommunications companies Nokia, Fujitsu, Motorola, and Sun Microsystems. He was arrested by the FBI in 1995, but later released on parole in 2000. He never termed his activity hacking, instead he called it social engineering.

1990
When a Los Angeles area radio station announced a contest that awarded a Porsche 944S2 for the 102nd caller, Kevin Poulsen took control of the entire city's telephone network, ensured he is the 102nd caller, and took away the Porsche beauty. He was arrested later that year and sentenced to three years in prison. He is currently a senior editor at Wired News.

1993
They called themselves Masters of Deception, targeting US phone systems. The group hacked into the National Security Agency, AT&T, and Bank of America. It created a system that let them bypass long-distance phone call systems, and gain access to the pbx of major carriers.

1995
Russian computer geek Vladimir Levin effected what can easily be called The Italian Job online - he was the first person to hack into a bank to extract money. Early 1995, he hacked into Citibank and robbed $10 million. Interpol arrested him in the UK in 1995, after he had transferred money to his accounts in the US, Finland, Holland, Germany and Israel.

1996
US hacker Timothy Lloyd planted six lines of malicious software code in the computer network of Omega Engineering which was a prime supplier of components for NASA and the US Navy. The code allowed a "logic bomb" to explode that deleted software running Omega's manufacturing operations. Omega lost $10 million due to the attack.

1999
The Melissa virus was the first of its kind to wreak damage on a global scale. Written by David Smith (then 30), Melissa spread to more than 300 companies across the world completely destroying their computer networks. Damages reported amounted to nearly $400 million. Smith was arrested and sentenced to five years in prison.

2000
MafiaBoy, whose real identity has been kept under wraps because he is a minor, hacked into some of the largest sites in the world, including eBay, Amazon and Yahoo between February 6 and Valentine's Day in 2000. He gained access to 75 computers in 52 networks, and ordered a Denial of Service attack on them. He was arrested in 2000.

November 2002
Englishman Gary McKinnon was arrested in November 2002 following an accusation that he hacked into more than 90 US military computer systems in the UK. He is currently undergoing trial in a British court for a "fast-track extradition" to the US where he is a wanted man. The last hearing in the case was on 15th Jan 2010.

GMail Manager




Gmail Manager

Gmail has now a days become the first choice email for many and very often we have more than 2 or 3 Gmail accounts. For instance you might have separate Gmail accounts for your blog, personal mail and work related email. As you might know that we at rtCamp use Google apps and I have a personal Gmail account. So monitoring multiple account makes sense for me.

Gmail Manager 0.6 which is a Firefox add-on. In the case you have some concerns having Greasemonkey scripts running on your browser from a security angle; Gmail manager makes a lot of sense.

About Gmail Manager

* Gmail Manager add-on can be downloaded by clicking here. Once the add-on is downloaded restart Firefox browser.
* The add-on options allows your enter your Gmail ID and Password. This will give you notification for any acocunt when you get an email.
* Just clicking on the relevant account will take you directly to your Inbox.
* If you hover your mouse pointer over the Account tag; you will get a pop-up which shows your emails that are in your inbox. Unfortunately you cannot go directly to the email from the pop-up. I guess that is what can be considered room for improvement.

If you are using Firefox browser and have a lot of active Gmail accounts Gmail Manager add-on is something which should interest you.

Download

Download Youtube Videos by Simply using the "OK" Word



Download Youtube Videos by Simply using the "OK" Word


Yes I consider this fun stuff knowing how many people are using various appz/tools/youtube-downloading sites and noooooooo neeeeeed for that

If you wanna move this - move - but I think it's fun stuff

Download Youtube Videos by Simply using the "OK" Word

Hi all....

Download videos from youtube by typing "OK"

yeah,it's not a joke...

type "OK" between www. and youtube...

Note::
adding OK will be downloaded in flv format

adding 3.OK will download in 3gp format

adding 4.OK will download in mp4 format

Nice Na............?? Enjoy and download loads of videos..........

Hide a file behind Image (without Any Software)



Hide a file behind Image (without Any Software)


To hide data in an image you need winRAR. First you add file into a rar archive as secret.rar. Now copy secret.rar file to a new folder. Now copy any image u want and paste it in folder of rar file as neture.jpg. Now open MS-DOS, go to the folder that contains secret.rar file and the image file and type "copy/b neture.jpg + secret.rar output.jpg"(without quotes). You'll now see an image called output.jpg in secret.rar's folder. Open it with WinRar. Only winrar can open the secret file in it. This can be opened by changing the extension to .rar.

Thursday, February 25, 2010

Get Rid Of the Blue Screen of Death


Get Rid Of the Blue Screen of Death



I have got a solution for the blue screen of death and from now you may never see the blue screen of death on your computer.

AntiCrash is a program that can intercept and fix up to 95.8% crashes, errors, freezes and blue screens. When a crash occurs, AntiCrash fixes it automatically; you have nothing to do!

New! AntiCrash now also includes a unique technology, AutoRepair. With AutoRepair, you scan & repair all your computer problems with a single click. AutoRepair automatically determines what is wrong on your computer with an advanced Artificial Intelligence system, and fixes it instantly.

AntiCrash will protect your computer like no other software. Not only AntiCrash protects you against 95.8% crashes, but it also automatically fixes the crashes; you don’t have to do anything, AntiCrash does all the work for you! AntiCrash is also the only software capable of intercepting blue screens and freezes.


To Download Anti-Crash_3.6.1 for free. Click Here

Use USB as RAM


Use USB as RAM


Windows ReadyBoost is a disk caching technology that helps make your operating system and application load faster by using flash memory for caching.
For this, put a Windows virtual memory file into a flash drive instead of a hard drive.

OR similarly,you can use eBoostr to perform windows ReadyBoost on xp platform and make use of XP’s prefetch data to cache files on a faster flash drive.

i've found a link of eboostr..
here it is..

Download it here

Another Trick to Enhance Internet Speed


Another Trick to Enhance Internet Speed
Follow these steps:-
Go to Desktop
Right Click on My computer Icon >-then click on "Properties"
then go HARDWARE tab
Device manager

In the Device Manager Window.........
Go to Ports
Communication Port(double click on it and Open).

Now you can see Communication Port Properties.
Go to Port Setting and now increase your "Bits per second" to 128000 and "Flow control" change to "Hardware".
Apply and see the result..... ...... ....... ENJOY

The Computer of Tomorrow

The Computer of Tomorrow !!!

The B-Membrane looks nothing like a conventional computer, more like a spaceship or space station, but it is indeed a PC, able to project an image of your desktop on any surface you can point its omni-directional projector at, thus rendering even the slimmest LCD monitor useless. It also has a membrane keyboard and mouse that appear only when you need them too, and an optical
 drive.













How to Break XP Administrator Password


How to Break XP Administrator Password

There was a loop hole in Windows XP. Which was discovered by the Microsoft personnel. U can Break Administrator Password by the following method:

1. Place your Windows XP CD(Bootable) in your cd-rom and start your computer 


2. Keep your eye on the screen messages for booting to your cd Typically, it will be “Press any key to boot from cd”

3. Once you get in, the first screen will indicate that Setup is inspecting your system and loading files.

4. When you get to the Welcome to Setup screen, press ENTER to Setup Windows now

5. The Licensing Agreement comes next - Press F8 to accept it.

6. The next screen is the Setup screen which gives you the option to do a Repair.

It should read something like “If one of the following Windows XP installations is damaged, Setup can try to repair it”

Use the up and down arrow keys to select your XP instruction
7. Let the Repair run. Setup will now check your disks and then start copying files which can take several minutes.

8. Shortly after the Copying Files stage, you will be required to reboot. (this will happen automatically – you will see a progress bar stating “Your computer will reboot in 15 seconds”

9. During the reboot, do not make the mistake of “pressing any key” to boot from the CD again! Setup will resume automatically with the standard billboard screens and you will notice Installing Windows is highlighted.

10. Keep your eye on the lower left hand side of the screen and when you see the Installing Devices progress bar, press SHIFT + F10. This is the security hole! A command console will now open up giving you the potential for wide access to your system.

11. At the prompt, type NUSRMGR.CPL and press Enter. NOw You have just gained graphical access to your User Accounts in the Control Panel.

12. Now simply pick the account you need to change and remove or change your password as you prefer. If you want to log on without having to enter your new password, you can type control userpasswords2 at the prompt and choose to log on.

How to Dual boot XP and Vist

How to Dual boot XP and Vista

Application compatibility remains one of the most annoying issues for Windows Vista users. The ability to upgrade the software to a new Vista compatible version is not always an option. The company that developed the application may no longer be around or the cost to upgrade is too high. In my case, I have a lot of classic PC games that will not run at all under Windows Vista no matter how I configure the compatibility options. In order to play my old games I need to install Windows XP. However, I am not exactly ready to give up all of the advances in Windows Vista just so that I can play my old games once in a while. The answer is to dual boot Windows Vista and XP. 

Dual booting Windows XP and Vista on the same computer will allow you to select from a boot menu what operating sytem you want to run. This menu is shown right after you power on your computer. Setting up both Windows XP and Vista on one computer can be a little ticky depending what operating system you have installed first. The next two sections will help you configure both versions on your computer, depending on what OS you have installed first:

If Windows XP is installed in your PC
If you want to dual boot XP and Vista and XP is already installed on your computer you will not have to do much work to dual boot vista. Just boot to your Windows Vista install DVD, select a custom install and install Vista on a separate partition or physical drive than where XP is installed. This will leave your XP install intact and automatically install a boot menu with both XP and Vista listed. 

If Windows Vista is installed in your PC
If you were like me and compley reformatted your hard drive and wiped out XP when you installed Vista, your setup is going to be a little more complicated. Follow these steps:

Boot up your computer with a Windows XP install CD and install Windows XP to a different partition or physical drive than where Vista is installed. When the setup is finished, your computer will automatically boot into Windows XP. Don’t worry, Windows Vista is still on your computer if you correctly installed XP to a different partition or physical drive.

When you installed XP, the Vista Boot Manager was replaced by the Windows XP boot components. The Vista Boot Manager needs to be fixed by using the Windows Vista install DVD. Boot your computer to the Windows Vista install DVD , click Next on the regional settings screen and then click on Repair your computer in the lower left of the window. Select your Windows Vista install and then run the Startup Repair. This will fix the Windows Boot Manager and Vista will once again startup automatically.

Now we need to add an entry to the Windows Boot Manger for Windows XP. This is done through Windows Vista. When you are back in Vista, open an administrative level command prompt window and run these commands:

bcdedit /create {ntldr} /d "Windows XP"
bcdedit /set {ntldr} device boot
bcdedit /set {ntldr} path \ntldr
bcdedit /displayorder {ntldr} /addlast

Reboot your computer and test out the new boot menu.

Dual boot has now been configured on your computer. You will be able to enjoy the enhancements of Windows Vista without giving up the ability to run older applications that require Windows XP.

<<<<<<<<<<<<<<<<<< Enjoy >>>>>>>>>>>>>>>>>>>

All about Firewall



What is a Firewall?

A firewall is a tool that monitors communication to and from your computer. It sits between your computer and the rest of the network, and according to some criteria, it decides which communication to allow, and which communication to block. It may also use some other criteria to decide about which communication or communication request to report to you (either by adding the information to a log file that you may browse whenever you wish, or in an alert message on the screen), and what not to report.

What Is It Good For?
Identifying and blocking remote access Trojans. Perhaps the most common way to break into a home computer and gain control, is by using a remote access Trojan (RAT). (sometimes it is called "backdoor Trojan" or "backdoor program". Many people simply call it a "Trojan horse" although the term "Trojan horse" is much more generic). A Trojan horse, is a program that claims to do something really innocent, but in fact does something much less innocent. This goes to the days where the Greek soldiers succeeded to enter through the gates of Troy by building a big wooden horse, and giving it as a present to the king of Troy. The soldiers allowed the sculpture to enter through their gates, and then at night, when the soldiers were busy guarding against an outside attack, many Greek soldiers who were hiding inside the horse went out and attacked Troy from the inside. This story, which may or may not be true, is an example of something which looks like something innocent and is used for some less innocent purpose. The same thing happens in computers. You may sometimes get some program, via ICQ, or via Usenet, or via IRC, and believe this program to be something good, while in fact running it will do something less nice to your computer. Such programs are called Trojan horses. It is accepted to say that the difference between a Trojan horse and a virus, is that a virus has the ability to self-replicate and to distribute itself, while a Trojan horse lacks this ability. A special type of Trojan horses, is RATs (Remote Access Trojans, some say "remote admin Trojans"). These Trojans once executed in the victim's computer, start to listen to incoming communication from a remote matching program that the attacker uses. When they get instructions from the remote program, they act accordingly, and thus let the user of the remote program to execute commands on the victim's computer. To name a few famous RATs, the most common are Netbus, Back-Orifice, and SubSeven (which is also known as Backdoor-G). In order for the attacker to use this method, your computer must first be infected by a RAT. 
Prevention of infections by RATs is no different than prevention of infection by viruses. Antivirus programs can identify and remove most of the more common RATs. Personal firewalls can identify and block remote communication efforts to the more common RATs and by thus blocking the attacker, and identifying the RAT.

Blocking/Identifying Other Types of Trojans and Worms?
There are many other types of Trojan horses which may try to communicate with the outside from your computer. Whether they are e-mail worms trying to distribute themselves using their own SMTP engine, or they might be password stealers, or anything else. Many of them can be identified and blocked by a personal firewall. 

Identifying/Blocking Spyware's/Adbots?
The term "spyware" is a slang which is not well defined. It is commonly used mainly for various adware (and adware is a program that is supported by presenting advertisements to the user), and that during their installation process, they install an independent program which we shall call "adbot". The adbot runs independently even if the hosting adware is not running, and it maintains the advertisements, downloads them from the remote server, and provides information to the remote server. The adbot is usually hidden. There are many companies that offer adbots, and advertisements services to adware. The information that the adbots deliver to their servers from the computer where the adbot is installed, is "how much time each advertisement is shown, which was the hosting adware, and whether the user clicked on the advertisement. This is important so that the advertisements server will be able to know how much money to get from each of the advertised companies, and how much from it to deliver to each of the adware maintainers. Some of the adbots also collect other information in order to better choose the advertisements to the users. The term "spyware" is more generic, but most of the spyware fall into this category. Many types of adbots can be identified and blocked by personal firewalls. 

Blocking Advertisements?
Some of the better personal firewalls can be set to block communication with specific sites. This can be used in order to prevent downloading of advertisements in web pages, and thus to accelerate the download process of the web sites. This is not a very common use of a personal firewall, though. 

Preventing Communication to Tracking Sites? 
Some web pages contain references to tracking sites. e.g. instruct the web browser to download a small picture (sometimes invisible) from tracking sites. Sometimes, the pictures are visible and provide some statistics about the site. Those tracking sites will try to save a small text either as a small file in a special directory, or as a line in a special file (depending on what is your browser), and your browser will usually allow the saving site to read the text that it saved on your computer. This is called "web cookies" or sometimes simply "cookies". Cookies allow a web site to keep information that it saved some time when you entered it, to be read whenever you enter the site again. This allow the web site to customize itself for you, and to keep track on everything that you did on that site. It does not have to keep that information on your computer. All it has to save on your computer is a unique identifying number, and then it can keep in the server's side information regarding what has been done by the browser that used that cookie. Yet, by this method, a web site can get only information regarding your visits in it. Some sites such as "doubleclick" or "hitbox" can collect information from various affiliated sites, by putting a small reference in the affiliated pages to some picture on their servers. When you enter one of the affiliated web pages, your browser will communicate with the tracking site, and this will allow the tracking site to put or to read a cookie that identifies your computer uniquely, and it can also know what was the web page that referred to it, and any other information that the affiliated web site wanted to deliver to the tracking site. This way tracking sites can correlate informationfrom many affiliated sites, to build information that for example will allow them to better customize the advertisements that are put on those sites when you browse them. 
Some personal firewalls can be set to block communication to tracking sites. It is not a common use of a personal firewall, though, and a personal firewall is not the best tool for that, but if you already have one, this is yet another possible use of it. 

Blocking or Limiting the NetBIOS Communication? (as well as other default services)
The two common methods of intruders to break into home computers, are through a RAT (which was discussed in II.3a) and through the NetBIOS communication. The NetBIOS is a standard for naming computers in small networks, developed long ago by IBM and Microsoft. There are a few communication standards which are used in relation to the NetBIOS. The ones that are relevant for Microsoft Windows operating systems, are: NBT (NetBIOS over TCP/IP), IPX/SPX, and NetBEUI. The communication standard which is used over the Internet, is NBT. If it is enabled, and there is no firewall or something else in the middle, it means that your computer is listening for communications over the Internet via this standard, and will react according to the different NBT commands that it gets from the remote programs. It is thus that the NBT (which sometimes loosely called "NetBIOS") is acting as a server. So the next question should be "what remote NBT commands the NBT server will do on the local computer". The answer to this question depends on the specific setting on your computer. You may set your computer to allow file and print sharing. If also NBT is enabled, it means that you allow remote users to share your files or printers. This is a big problem. It is true that in principle the remote user has to know your password for that computer, but many users do not set a password for their user on Windows, or set a trivial password. Older versions of Win95 had file and print sharing over NetBIOS enabled by default. On Win98, and WinMe it was disabled by default, but many technicians, when they set a home network, they enable the file and print sharing, without being aware that it influences also the authorizations of a remote Internet user. There are even worms and viruses who use the File sharing option to spread in the Internet. Anyway, no matter whether you need it for some reason or just are not aware of it, a personal firewall can identify and block any external effort to communicate with the NetBIOS server on your computer. The more flexible personal firewalls can be set to restrict the authorization to communicate with the NetBIOS. Some Windows operating systems, especially those which are not meant for home uses, offer other public services by default, such as RPC. A firewall can identify communication efforts to them, and block them. Since such services listen to remote communications, there is a potential risk when there are efforts to exploit security holes in the programs that offer the services, if there are such security holes. A firewall may block or limit the communication to those services. 

Hiding Your Computer on the Internet? 
Without a firewall, on a typical computer, even if well maintained, a remote person will still be able to know that the communication effort has reached some computer, and perhaps some information about the operating system on that computer. If that computer is handled well, the remote user will not be able to get much more information from your computer, but might still be able to identify also who your ISP is, and might decide to invest further time in cracking into your computer. 
With a firewall, you can set the firewall so that any communication effort from remote users (in the better firewalls you may define an exception list) will not be responded at all. This way the remote user will not be able to even know that it reached a live computer. This might discourage the remote attacker from investing further time in effort to crack into your computer. 

The Non-Firewall Defenses 
We've discussed a few situations where a personal firewall can provide defense. Yet, in many cases a computer maintainer can deal with those situations even without a firewall. Those "alternative" defenses, in many cases are recommended regardless of whether you use a firewall or not. 

Remote Access Trojans?
The best way to defend against remote access Trojans (RATs) is to prevent them from being installed in the first place on your computer. A RAT should first infect your computer in order to start to listen to remote communication efforts. The infection techniques are very similar to the infection techniques that viruses use, and hence the defense against Trojan horses is similar to the defense against viruses. Trojan horses do not distribute themselves (although they might be companions of another Internet worm or virus that distributes them. Yet, because in most cases they do not distribute themselves, it is likely that you will get them from anonymous sources, such as instant messengers, Kazaa, IRC, or a newsgroup. adopting a suspicious policy regarding downloads from such places, will save you not only from viruses but also from getting infected with Trojan horses, including RATs. Because Trojan horses are similar in some ways to viruses, almost all antivirus programs can identify, block from being installed, and remove most of the Trojan horses, including all the common ones. There are also some programs (sometimes called antiTrojan programs) which specialize in the identification and removal of Trojan horses. For a list of those programs, and for comparison on how well different antivirus, and antiTrojan programs identify different Trojan horses, see Hackfix (http://www.hackfix.org), under "Software test results". Hackfix also has information on the more common RATS (such as the Netbus and the Subseven) and on how to remove them manually. There are some tools and web sites, such port scanners, and some ways with a use of more generic tools such as telnet, msconfig, and netstat, which may help you to identify a RAT. 

Other types of Trojans and worms? 
Also here your main interest should be to prevent them from infecting your computer in the first place, rather than blocking their communication. A good antivirus and a good policy regarding the prevention of virus infections, should be the first and most important defense. 

Spyware and Adbots?
The term spyware is sometimes misleading. In my view, it is the responsibility of the adware developer to present the fact that the adware installation will install or use an independent adbots, and to provide the information on how this adbot communicates, and which information it delivers, in a fair place and manner before the adware is installed. It is also a responsibility to provide this information in their web sites, so that people will be aware of that before they even download the software. Yet, in general, those adbots do not pose any security threat, and in many cases also their privacy threat is negligible for many people (e.g. the computer with adbot number 1127533 has been exposed to advertisements a, b, c, such and such times, while using adware x, while on computer with adbot number 1127534 has been exposed to advertisements a,d, and e, such amount of time, with the use of adware y, and clicked on ads number d). It should be fully legitimate for software developers to offer an advertisement supported programs, and it is up to the user to decide whether the use of the program worth the ads and the adbot, or not. Preventing adbot from communicating is generally not a moral thing. If you decide to use an adware, you should pay the price of letting the adbot work. If you don't want it, please remove the adware, and only if for some reason the adbot continue to work even if no hosting adware that uses it is installed, you may remove the adbot. Anyway, there are some very useful tools to identify whether a program is a "spyware", or whether a "spyware" is installed on your computer, and you are certainly entitled to this information. Two useful programs are "AdAware" which identifies "spyware" components on your computer and allows you to remove them, and Ad-Search which allows you to provide a name of a program, and it tells you whether this program is a "spyware" and which adbot it uses. It is useful to assist you in choosing whether to install a program or not. You may find those programs in http://www.lavasoft.nu (or, if it doesn't work, you may try http://www.lavasoftusa.com). Those programs are useful, mainly because many adware developers are not fair enough to present this information in a fair manner. AdAware allows you to also remove those adbot components from your computer. This might, however, terminate your license to use the hosting adware programs, and might even cause them to stop functioning. A website which offers to check whether a specific program that you wish to install is "spyware" or not, is http://www.spychecker.com . 

Blocking Advertisements?
Leaving aside the moral aspect of blocking advertisements, a personal firewall is not the best tool for that anyway. This is not the main purpose of a firewall, and neither its main strength. Some of them can block some of the advertisements from being downloaded, if you know how to configure them for that. Yet, there are better tools for that, such as Proxomitron (http://www.proxomitron.org), CookieCop 2 (search for the word cookiecop on http://www.pcmag.com), or Naviscope (http://www.naviscope.com), and there are many other programs as well. You may check for other alternatives, e.g. in Tucows (http://www.tucows.com/adkiller95.html). 

Blocking Tracking Sites?
Also here, a personal firewall is not the best tool for that, and there are other tools and ways which are more effective. These are cookie utilities. Since a tracking site uses a cookie to identify and relate the information gathered to the same person (or computer), by preventing the cookie from being installed. The tracking site will lose its ability to track things. There are plenty of cookie management utilities. Some of them are freeware, and some are not. CookieCop which was mentioned in the former section is one of them. WebWasher (http://www.webwasher.com) is another recommended one, and there are plenty of other alternatives such as cookie-crusher, cookie-pal, pop-up killer, etc. You may search for other alternatives, in Tucows (http://www.tucows.com/cookie95.html).

NetBIOS and Other Services?
The NetBIOS over TCP/IP (NBT) which is sometimes loosely called "NetBIOS", is a service which has some security problems with it. It is enabled by default in Windows default installations, and it is very common to see that a firewall does the job of preventing the efforts to get access to your computer via NBT. Yet, in almost all cases, this service is not needed, and thus can be disabled. To disable NBT in Win95/98/ME is not as simple as it is in Win2K/XP, but can still be done reliably. We explain how to do this in another article (#to be written soon). It is needless to say, that if NBT is disabled, there is no need for a firewall to block communication to it. Also, in the case of other services, such as RPC services, and others, in many cases you simply don't need those services and better disable them from within Windows rather than use the firewall to block them. There are various ways to know which services are running on your computer, and which of them are listening for communications from the outside. If there are ones that you don't need, they should be disabled. 

Hiding the Computer?
In web sites of many personal firewall companies, they are putting a lot of weight on the ability of their firewall to hide the computer on the Internet. Yet, exposing your home computer on the Internet is by itself, neither a security nor a privacy threat. If you provide some services to the Internet on your computer, for example, you put a web server on your computer to allow other people to view web pages, then you might get rid of some of the crackers, by setting your firewall to unhide only this type of communications. Some attackers will not make a full scan of your computer, but only a partial scan, and if they did not scan for the specific service that you provided, they will not see your computer. Yet, if the service is a common one, there is a good chance for many of them to scan it and thus find the existence of your computer. If they "see" the existence of your computer, they might decide to scan it further, and find out the services you are providing, and scan it for security holes to use. Yet, there is no much meaning to it when we speak about simple home computers.

What a Firewall Cannot Do!
Another mis-conception about personal firewalls is that they are incorrectly thought as if they claim to give an overall protection against "hackers" (i.e. intrusions). They are not. 

Defense Against Exploitation of Security Holes
A firewall can allow or deny access to your computer or from your computer according to the type of communication, its source and destination, and according to the question which program on your computer is handling the communication. Yet, its ability to understand the details of the communication is very limited. For example, you may set the firewall to allow or to deny your e-mail program from getting and/or sending messages. It may allow or deny your web browser from browsing the Internet. But if you allowed your e-mail program to communicate with the e-mail servers for sending and receiving messages, (and you are likely to allow it if you want to use your e-mail program), or if you set the firewall to allow your web browser to communicate with web sites, the firewall will not be able to understand the content of the communication much further, and if your web browser has a security hole, and some remote site will try to exploit it, your firewall will not be able to make a distinction between the communication that exploits the security hole, and legitimate communication. The same principle goes with e-mail program. A personal firewall may block you from receiving or sending e-mail messages, but if you allowed it to receive messages, the personal firewall will not make a distinction between a legitimate message and a non-legitimate one (such as a one that carries a virus or a Trojan horse). Security holes in legitimate programs can be exploited and a personal firewall can do practically nothing about it. 
I should comment, however, that some personal firewalls come combined with some Trojan horse detection, or intrusion detection. This is not part of the classical definition of a firewall, but it might be useful. Such tasks are usually taken by other tools such as antivirus programs or antiTrojan programs.

Tricks to Bypass or Disable Personal Firewalls
There are also various ways to disable, or bypass personal firewalls. During the time a few tricks to bypass or disable were demonstrated by various programs. Especially, tricks for an internal program to communicate with the outside bypassing or tricking the firewall. For some of them such as the one demonstrated by the Leaktest, and in which a non-legitimate program disguises itself as Internet Explorer, practically today, all personal firewalls are immuned. For other tricks, such as a one demonstrated by Outbound, which uses some non-standard type of communication directly to the network adapters bypassing the components of the operating system which are suppose to deal with Internet communication, and by that bypassing the firewall, are only now being patched against by the various firewalls, and yet other methods, such as the one demonstrated by Tooleaky, which uses Internet Explorer as a messenger to communicate with the outside, and is thus identified as a mere legitimate browsing, are still waiting for most of the personal firewall to find a fix. 

Firewalls CANNOT Decide for You What is a Legitimate Communication and What is Not 

One of the main problems with personal firewalls, is that you cannot simply install them and forget them, counting on them to do their job. They can deny or permit various types of communications according to some criteria, but what is this criteria, and who decides what is the criteria for whether they should permit or deny some communication? 

The answer, is that it is the computer user's job to define the exact criteria when the firewall should allow a communication and when it should block it. The firewall may make it easier for you, but it should not take the decisions. There are too many programs, too many versions, and it is not possible for the firewall to decide accurately when a communication is legitimate and when it is not. One person might think that it is legitimate for some program to deliver some information to the outside in order to get some service, while another will think that it is not. One version of a program might communicate with its home server in order to check whether there is an upgrade, and another version might also install the upgrade even if you do not wish. Some firewalls will try to identify communication efforts which are largely considered as legitimate, and will let you the information so that it will be easier for you to decide whether such should be allowed. Others will suffice with more basic information, making no suggestions (and thus - no incorrect recommendations). One way or another, once you installed a firewall, you will have better means to understand what types of communications are running on your computer, but you will also have to understand them in order to be able to configure your firewall so that it will correctly know which communications to allow and which to block. 

Common Problems and Deficiencies Regarding Personal Firewalls 
A personal firewall might be a good contribution to security. Yet, if you do not understand much about the topic, then you are likely to be confused and misled by its alerts and queries, and thus find yourself spending hours in chasing after imaginary crackers, fear from imaginary threats, and misconfigure it due to misunderstanding. You may find yourself blocking legitimate and important communication believing it to be cracking efforts, and thus surprised to see why things work slowly or why you are disconnected from the Internet, or you might be misled to allow a non-legitimate communication by some software that tricked you to believe that it is a legitimate one. On the other side, if you are quite knowledgeable on computers and security, then you are likely to effectively defend your computer even without a firewall (by means discussed in section II.4) and it is thus that the role of personal firewall in securing your computer, is extremely small and not much important. We discuss here in brief some of the problems that personal firewalls may generate. 

A False Sense of Security 
As we've already learned here, a firewall is limited in its ability to secure your computer. Yet, many people believe that if they will install a personal firewall they will be secured against the various security threats. I was even surprised to find out that there are people who believe that give much higher priority in installing a personal firewall than in installing an antivirus program. An always updated antivirus program plays a much more important role in the security of a personal home computer than installing and maintaining a personal firewall. A personal firewall should not come on account of any other security measure that you use. 

When you install a firewall and you look at all the communication efforts through it, you might be surprised at the amount of communication efforts from the Internet to your computer. Most of them are blocked by a typically configured firewall. There are all the times efforts to try to communicate with various backdoor Trojans on your computers. If you are not infected, there will be nothing to listen and to respond to those communication efforts, and they are thus practically harmless. There are efforts to communicate with your NBT driver, to see if your computer by mistake allows file sharing. There are other types of probes to see if your computer exists, or various efforts of servers to probe your computer in order to find the best path for legitimate communication to it. There are sometimes remnants of communications that were supposed to go to other computers, but made their way to yours (for advanced readers: because the IP number that your computer uses, were used by some other computer earlier). Those communication efforts are blocked even without a firewall. If your computer is not infected with a RAT, and if your computer don't have NetBIOS over TCP/IP enabled or even it does not have file and print sharing enabled (and on most computers this is disabled by default), then none of these pose any security threat. If your computer is not infected with a SubSeven Trojan, then no matter how often there will be efforts to communicate with it, they are all doomed to be failed. 
Yet, some personal firewall (such as Norton Personal Firewall or ZoneAlarm) by default proudly announce that they have just blocked an effort to crack into your computer. Norton may even define those efforts that were blocked as "high security threats" while they were not a threat at all even if your computer didn't have a personal firewall at all. Such firewalls give you the false impression that they save your computer again and again from extremely dangerous threats on the Internet, so that you wonder how did you survive so much time without noticing any intrusion before you installed the firewall. I usually say, that those personal firewalls are set their "report level" to "promotional mode". Namely, the personal firewall is set to give you the false impression that it is much more important than it really is. 

Chasing After Ghosts 
This is a side effect of the types of misunderstandings that were discussed in the previous subsection. 
When a person who starts to learn about the jargon related to personal firewalls, is reported that some "dangerous" communication efforts persist from the same source, the person is decisive to locate and identify the "hacker", and perhaps report about it to the police or to its Internet service provider. However, since many people do not really understand thoroughly how things work, they may sometimes spend many hours in trying to locate a cracker that does not exist, or when the knowledge they need to have, in order to track the cracker, is much higher than what they have, and they might even suspect the wrong person due to lack of knowledge (e.g. the connection person on the Internet service provider that was used by the cracker). More knowledgeable people, usually do not bother to track those "hackers" (which are usually teenagers), but instead are concentrating on the security of their computer. 

Blocking Legitimate Communications 
No personal firewall is smart enough to decide for the user what is a legitimate communication and what is not. A personal firewall cannot make a distinction between a legitimate program trying to contact its server to check and notify the user when there is a newer version, and a non-legitimate program trying to communicate with its server in order deliver sensitive information such as passwords, unless the user tells it. It is thus up to the user to decide what should be considered as legitimate and what should not. Yet, can we count on the user to be knowledgeable enough to decide what is legitimate and what is not? In many cases the user is not knowledgeable enough, and may thus allow non-legitimate communication or disallow a legitimate and important communication. There are many types of communications handled just to manage other communications. Among this are various types of communications between your computer and the various servers of your Internet service provider. A not knowledgeable user may interpret those types of communications as cracking efforts, and will thus decide to block them. As a result, a connection might become slower, a connection to the Internet service provider might be disconnected quiet often and other types of communication problems. 

Being Tricked by Trojans
Just as less knowledgeable users may instruct the firewall to block legitimate communications, they can be tricked by various Trojans to allow them to communicate. Some Trojans are using names resembling or identical to names of legitimate programs, so that the user would think that it is a legitimate programs. Users should be aware of that. 

Heavy Software, Buggy Software 
Until now we discussed only problems related to lack of appropriate knowledge by the user. Yet, there are other problems regarding personal firewalls. For example, some of them are known to be quite heavy on computer resources, or slow down the communication speed. Different personal firewalls quite vary with regard to that. If you have a new computer with a slow Internet communication (such as regular dial-up networking) then it might not slow down your computer noticeably. Yet, if you use an older computer, and a fast communication, you might find that some personal firewalls will slow down your communication quite drastically. Personal firewalls also vary on how much they are stable. 

Advantages of External Firewalls over Personal Firewalls 
1. They do not take resources from the computer. This should be clear. This is especially useful when the firewall blocks flooding attacks. 
2. It is harder (although in principle still possible) for a Trojan horse to disable it, because it does not reside in the same computer that the Trojan has infected. It is not possible to use the specific communication while totally bypassing the firewall. 
3. They can be used without any dependence on the operating system on the computer(s) they defend. 
4. No instability problems.