Viruses Viruses

I just got done running AntiVir on this computer, and was surprised to find that I had over a half a million files on it, with 16,000 directories. And after that, it only found one virus in one executable (restart.exe) replicated three times. It appears to be a Windows NT 4.0 systems file, and I guess I need to update that if I ever want to run NT 4 again.