Stop Error

Short answer is that windows is damaged and needs to be re-installed.

STOP C000021A (Fatal System Error)
The session manager initialization system process terminated unexpectedly with a status of 0xC000026C (0x00000000, 0x00000000). The system has been shut down.

STOP: c000021a {Fatal System Error}
The windows logon Process System Process terminated unexpectedly with a status of 0xc000012f
0x0000000000, 0x00000000000)
The system has shut down.


http://support.microsoft.com/kb/891534

http://support.microsoft.com/?kbid=316503&sd=RMVP

This error can occur when you have GoBack installed on your computer and it is present in the boot sector.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xpehelp/html/xeconc0000034objectnamenotfound.asp

Description
When you attempt to boot your target system, a blue screen is displayed with the message "c000021a".

The most common cause of this error is a missing device driver dependency. This can occur even if the device driver is not critical for the system to boot. For example, Redbook.sys is not required to boot the system. But if one of its dependencies, Ks.sys, is not included in the run-time image, the system displays the error code 0xc000021a.

Resolution
Identify missing dependencies. For information, see Checking Dependencies.
If you determine that a dependency is not missing, then the error probably occurred because a file that the driver depends on is missing. Use the Microsoft® Visual Studio® Depends utility, which runs using the Depends.exe file, to view the statically loaded libraries. The libraries are located in the import section of the binary file. Search for required files that are missing from your run-time image.