Do u guys have limewire or something?
I remember that hapennig to me.
u have a bad copy, if u delete it, and find it there when you restart your pc or something, u have a virus.
Another really really really annoying virus is onoes.exe
that virus will not let go, and disables alot of stuff including system restore.
I had to do a manual reinstallation of windows. now everything works fine, until i give my self an idiot choice of opening a bad file, and most of the time i do, and i end up with a virus.
System restore is a friend, and an enemy.
Aslo, go to your hard drive and look for files that do not belong.
if they keep coming back, ask someone good in PC's to help you out.