System: Windows XP Media Centre Edition,
Issue: System starts, user enters username and password. Windows loads, Startup theme, but before any icons on desktop appear on desktop, machine logs out back to screen asking for username and password.
Am able to log in via Safe Mode.
Fix: Appears virus activity had corrupted userinit.exe within C:WindowsSystem32
Simply replaced this with one from a working PC. Restart and machine was running correctly again.
Link: Many
Images: Will Post