Where was this service call: (Belmont and Lake Shore Dr.)

That can be easy fix, if you know what’s causing the problem. My customer could not login in any of his accounts, not even in safe mode. He tried with his own account, the guest account and the administrator account. As soon as he was logged in, he was dropped back to the login screen.

The common cause for this issue is the fact that c:\windows\system32\userinit.exe is deleted by either a spyware program, or a anti-spyware program that tries to clean your computer. This is documented in detail in a Microsoft Knowledge Base: You cannot log on to Windows XP after you remove Wsaupdater.exe

I just copied userinit.exe from my BartPE rescue cd to his system32 directory and that was it.

His computer was pretty much free of spyware because he uses Firefox for browsing and he has a subscription to Norton Internet Security.