XP constant reboot after WinUpdate

Hello,
A computer I built myself constantly reboots. It will go to the "safe boot" screen (without my prompting) and will not boot into any boot type I choose, not safe or anything else. The "Microsoft malicious removal tool" will flash (in DOS letters) for a moment, then reboot before the splash screen ever shows. The last thing I did was upgrade that removal tool through Windows Update, then it started doing this after the reboot.

I have tried to do a Windows repair (took an hour) and it worked, once. I got my desktop (drivers restored from CD so old) and I tried to reboot again, then got the "safe boot" screen again. Reboots continue.

How can you uninstall a removal tool that starts before Windows? Hunted the Microsoft site, but nothing.
Help.