[decadence]

Not a virus as such because it's unlikely the program you downloaded replicates itself in order to propagate.

It's simply a trojan or malware. Basically a deliberately destructive program. I experienced the same thing once as I mentioned in an earlier post.

Define reinstalling everything? Or do you want to speak to me on AIM maybe?

ETA: Ohh I see what you mean. Well if it deleted say MS Office then that'd need reinstalling too (chances are its CD can repair it rather than have to wholly re-install). You'd know once you tried to run it what was deleted and what wasn't. If it deleted all the Windows system files for example then yes it would have messed up most programs.