Hi! I have the same problem, only all of my Windows XP Pro system files seem to be infected. I use two hard drives with two separated systems (Win7 and XP Pro, not even any boot record recognizes the other), and the Win7 seems to be okay.
I just refreshed both the virus database and the software, and it's still coming up. I'm not sure if it's a mistake though. What is worse, WinXP tells me to use the original install disc to repair the files, because "necessary system files have been replaced with unrecognizable versions" or something like that, that may affect stability. I lost some programs too (like notepad.exe), I think those have been moved to quarantine. If I move to quarantine all the system files of WinXP I'm sure it won't ever start again, and I need that system. Repair didn't work. Any idea?