While I was on my computer today, my antivirus software suddenly popped up with a malicious file.

Without looking at it, I quarantined the file and decided to look at it later.

A few minutes after that, my computer was suddenly bogged down. For no reason, My Documents popped up on my screen. I checked my PC processes-- lo and behold, my computer was using up 63% of it's resources. It was moving so slowly that I couldn't even scroll through the list to see if anything suspicious was running.

So I rebooted my computer and started in safe mode. I ran all of my antivirus scans and they all came up with the same file: userinit.exe

Again, because I wasn't thinking (if I had been, I would have realized this was the system login process) I had my antivirus delete the file.

Now I can't log in.

The obvious solution was to, of course, dig out my windows XP disc and try to load the file again. No such luck-- I don't get the option to run a repair install when I use the boot disc. There's a blue screen with 'Windows Setup' at the top, and it gives me the option to set up a RAID drive or to run window's automated recovery.

I really don't want to lose any files over this, if possible.

Thanks in advance.