do a v scan i u have gon on the net without a av on it. Thers a very small chance u may have picked summin up. Happeded to me on a very regualr basis when i was trying to update my av deffs kept on getting W32.Welchia.B and that were a pain in the ass. As soon as i loged on to the net bam every time.
Good point. BTW dont bother with xp 64 because all the reviews i have read make out that its the worst windows os ever! If you want 64 bit go for linux or bsd as most have been 64bit for a long time now.