what is wrong with my system?

i get home from work yesterday, turn on my computer, and got a lovely winlogon.exe error. and then when it rebooted on me, it looked like i was playing kingdom of Zorg( a bunch of colorful blocks) resetting my cmos doesnt do anything. do i need to reinstall/fix my os?

Try booting using the "Last Known Good Configuration" (hit the F8 key directly after POST to access the startup option). If that doesn't help, then try replacing Winlogon.exe from the Recovery Console...

How To Replace a Driver by Using Recovery Console in Windows 2000
http://support.microsoft.com/kb/313670
(Also applies to XP)

If that doesn't help...

How to troubleshoot a "STOP 0xC000021A" error
http://support.microsoft.com/kb/156669

...and if all else fails:

How to perform an in-place upgrade (reinstallation) of Windows XP
http://support.microsoft.com/kb/315341/

Try this in the command prompt:

sfc /scannow

You'll likely need your installation cd.

Forgot to tell you what sfc /scannow does. It will try to restore missing or corrupt Windows Protected Files. The scan will take a while, but a progress bar will be shown. You should probably restart afterwards.