windows xp pc freeze - system has recovered from a serious error

Hello all.

I'm working on a computer with Windows XP Pro. The power supply failed and I replaced it. While I was there I thought I would go ahead and check it for needed updates. It needed 84 of them. I went ahead and downloaded and installed them. There were two anti-viruses on the machine so I removed one. There were some start up errors so I went to MSCONFIG and unchecked the offending lines. A message stating the system has recovered form a serious error had also appeared.

After a mandatory re-boot, the same error messages appeared including the serious error message. Also the normal diagnostic warning did not appear as is usual for changes made in the MSCONFIG menu. The removed software was still installed. The unchecked lines in MSCONFIG were rechecked. It is as if the computer is "locked" in time and will not accept updates or changes. Even after going through the Microsoft Security Essentials updates, those updates were not there after a re-boot.

I'm lost at this point. I can surf with out being re-directed by something. I downloaded a root kit detection software program and ran that. Both the anti-virus and root kit programs found nothing. Any ideas?

Have you tried starting up the pc in safe mode and checking whether it is still giving issues based with the system recovey error and the msconfig? What all start up items were disabled by you, can you list them? Also, having 2 antivirus system installed on one system can also cause serious damage, so first try to uninstall both the antiviruses from your system completely, using its some kind of uninstall tool and then install any one of the antivirus program again and then scan for viruses. After that let us know the results. By the way what all antiviruses were installed in your computer?

I've tried both safe mode and regular mode. The two anti-virus programs are: Norton scan (One of those drive by installs from some update) and Microsoft Security Essentials.

I go to Add - Remove programs, uninstall the Norton software and get a green light that it has been remove. As long as I do not re-boot any changes I make stick. For example, a wired network connection was disabled. I re-enabled it and everything works fine. If I reboot after updating Windows or anything else, those changes are lost. Even If I make the changes in Safe Mode.

There is a password menu prompt when you boot up. There is no password as all you have to do is hit enter to proceed.

I looked around in the administrator area of the control panel and there are no passwords stored, no restrictions set up for the administrator or guest user.

In safe mode there are errors from the MSCONFIG menu that I shut off. Still no prompts that I have altered that menu upon re-boot in safe mode. The serious error message does not appear in safe mode. It will appear in regular mode every time.