I have tried to install service pack 3 and my computer locks up with a Stpo: C000021a { fatal system error.. What do i do now??

The errors in computers make it miserable for their users to use them. They face so many problems when computers do not perform as intended. A very common error, which computer users can face, is the c000021a fatal system error.
This error is produced when it found by Windows NT kernel that either of the two processes Csrss.exe or Winlogon.exe has failed. Such processes could have stopped working due to many reasons like misaligned files being installed on the PC and a faulty restoration of files at the place where they were being used. In the event of such a situation, the Windows NT kernel stops the system and the stop c000021a fatal system error message is produced on the screen. This kind of a fatal exception happens when the PC can't tackle an exception and the program showing it needs to be closed.
This kind of a c000021a unknown hard error can be resolved by uninstalling the software that is not as per the needs of your PC. One can remove all the unwanted files present on the PC. An upgrade of the PC's operating system is also an alternative to restore it to its working condition and fix the stop c000021a unknown hard error.
The second solution to fix c000021a error from your computer is also very simple. You do not need to feel much hassled because of it. Just restart the computer. When the computer is booted, press the F8 button. Choose the last known good configuration and then press enter. This error generally happens when some software or hardware has been installed that is not as per the specifications of the PC. Therefore, after selecting the operating system you want for booting, the C000021a error will have been removed from your system.
However, it is better to utilize a registry cleaner software when the error still does not go away.
Windows registry includes all the information that is used by this operating system for carrying on with any operations like creation of documents. Windows Kernel uses all this information for executing the applications.
Registry cleaner software can ensure that the registry is cleaned of all the bad entries which have been causing an improper execution of files by Windows Kernel. Using this software is one of the most effective ways to fix the c000021a fatal system error. It can clean the registry without deleting any useful items from it which can lead to production of further errors.

Fix C000021a Fatal System Error is easy to do with registry cleaner. If you Scan Your Computer it will detect all the errors in your registry and safely remove them.

Hi. The STOP 0xC000021A error occurs when either Winlogon.exe or Csrss.exe fails. When the Windows NT kernel detects that either of these processes has stopped, it stops the system and raises the STOP 0xC000021A error. This error may have several causes. Among them are the following:

• Mismatched system files have been installed.
• A Service Pack installation has failed.
• A backup program that is used to restore a hard disk did not correctly restore files that may have been in use.
• An incompatible third-party program has been installed.

Booting the computer to its Last known good configuration will resolved the issue. Please see procedure below:

Turn of the computer
Keep on tapping F8 key the moment you press the power button
You should be getting a advanced boot screen
Select Last known good configuration from the selections then hit enter
Computer should be booting up by now to windows

All the best!

If you attempt to install a piece of hardware or software on your PC computer that is incompatible with your system, you may see a blue screen with a C000021a fatal error warning. The easiest way to recover the Windows operating system from this type of error is to restore your computer to a previously working state.
1.Press the "F8" key on your keyboard when prompted during the boot process.

2.Use the up-and-down arrow keys to highlight the "Last Known Good Configuration" option. Then hit "Enter.
3.Use the up-and-down arrow keys to highlight the operating system version that you wish to boot up to, and then hit "Enter" again. The system will now restart to the last working version of your operating system, which will eliminate the C000021a fatal error.
Hope this helps

start in safe mode with command propmpt and type chkdsk /r/f and let the system get scan.

In my experience, your computer's hard drive might be fried. I took a couple computer architecture classes and this seems to be the most reasonable answer. if I were you, i would find a computer technician just to be sure. Hope this helps, good luck
here are a few websites that might help
http://healyourchurchwebsite.com/2008/03/14/how-i-fixed-my-stop-c000021a-fatal-system-error-with-knoppix/

http://forums.techarena.in/windows-xp-support/771529.htm

hello there
here is some information that should be able to explain this error and how to fix it ok?
best regards michael

1. How to troubleshoot a "STOP 0xC000021A" error ... presents advanced troubleshooting steps for the STOP 0xC000021A error. ... STOP: c000021a {Fatal ... Note Most STOP 0xC000021A errors occur because Winlogon. ...support.microsoft.com/kb/156669
2. "STOP: c000021a (Fatal System Error)" Error! RE: "STOP: c000021a (Fatal System Error)" Error! Ya, thats what I thought I might have to do ... RE: "STOP: c000021a (Fatal System Error)" Error! just input the ...www.msghelp.net/showthread.php?tid=66202 - 52k - Cached
3. How I fixed my Windows XP Stop c000021a {Fatal System Error} with ... How I fixed my Windows XP Stop c000021a {Fatal System Error} with Knoppix Linux. 2008 March 14 ... Message: Stop c000021a {Fatal System Error} The Session ...healyourchurchwebsite.com/2008/03/14/how-i-fixed-my-stop-c000021a-f... - 53k - Cached

Next step is remove hard drive and see if it is recognized in another computer. The Hard Drive could just be bad, but you need to rule out the motherboard drive controllers that could also be bad. Also try a known good drive in your system.

Char S.

usually blue screen comes from unstable video memory or windows system or HD.
you may try
1) reinstall windows
2) change another HD to install windows
3) change new ram memory or change memories slot between one and another
if not fixed, to be sure your video memory damage which is insualted on board(separated with RAM), only the hardware repair can be fixed.

How do you mix this problem?