after sp3 update - no more user access

I updated XP from SP2 to SP3 and after that, whenever I go into my username and get to the desktop, the computer says it is logging that username off and shuts down. The same thing happens in Safe Mode where I have no Admin as a username.

I spoke with a computer person who told me this is a sign the XP copy is illegal, but I've been using this copy for around 5 years, reinstalling and updating to SP3 up with no problem. I've been able to activate it after new installations with both an old and a new motherboard and harddrives.

Can anyone tell me what the problem might be and if there is any solution short of reinstallation?

I currently have access to the computer from a separate partition.

 

This article might help. Taking ownership.

-> http://support.microsoft.com/?kbid=308421

I have an XP pro service pac 1 that I've updated to service pac 2, then 3 using auto updates with 1 prob. Might of gotten a bad download? Downloading service pac 2 at the time, it was corrupted. I had to order the disk. No hick-ups installing it. When service pac 3 was recomended by auto-updates. It installed great. My computer is set up pretty much the same as yours on admin privliges.

 

I'm not sure this is quite the same problem because I can't log on. It recognizes the name but just saves the settings and logs back off again. Would it be possible to put a different operating system on the computer and try to take ownership of the username from another partition and operating system?