Is this a virus?

[theforce]

I am running vista and xp on the same computer with no problems. They are installed on different physical drives and yesterday i tried to log into XP. Everything is ok it loads xp and then before it gets into desktop it sais that a file is missing and there is only a black screen.
Is this the result of a nasty virus or something? I was using AntiVir on XP and it showed everything was ok. Heard that AntiVir was a good antivirus. Also the disk seems to be ok since i can open files and folders from my hard disk xp is on through Vista.
Any ideas?

 

[SiriusB]

What file is missing?

You could also try booting into XP in Safe Mode and doing a virus scan.

Never heard of AntiVir so I would probably download one of the other free AVs like AVG or Avast, see if they turn anything up.