WinXP Logs Off As Soon As I Log In

Cause: Cust got the a spyware called SEARCH ASSISTANT installed on their machine.

Windows SA (Search Assistant) . But uninstalling doesn't revert it back.
Some adaware programs may also remove or quarantine wsaupdater.exe thinking that it's harmful.

Fix:
1. Boot using your winxp cd.
2. Enter recovery console.
3. at the command prompt go to
C:/windows/system32
4. next type:
copy userinit.exe wsaupdater.exe
5. exit and reboot normally. You should now be able to logon. But you're not done yet!
6. run regedit
7. find the Userinit key in:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
8. change the entry:
C:\WINDOWS\System32\wsaupdater.exe, <---don't forget the comma
to:
C:\WINDOWS\System32\userinit.exe, <--don't forget the comma