I have several programs on my computer waiting to be installed, such as Stanford's Folding@Home. Unfortunately, when I try to install them, they try to install mp3 surgeon for me instead.

This is not the first time it's happened, but it's really annoying at this point. AVG doesn't detect anything. Does anyone else know what might be going on in my machine? (I couldn't google up anything either). Thanks.

Of course I don't know the exact nature of your problems, but I learned that besides virusses there are spybots as well.
Some nice software to start cleaning your system could be SpyBot S&D or Ad-Aware If you never used them before you'll be quite surprised what kind of garbage has been installed on your box while simply surfing the web with IE.
Trying an alternative webbrowser could help as well, Opera could be a candidate (If you do not need it, disable Java support for even more stability)

Just a stab in the dark, but that sounds more like an issue with an old .msi file--if you're running xp, try using the installer cleanup in your programs>support tools folder(maybe on your actual windows cd). It can't hurt, whenever I check it out, something always seems to have chosen a lousy way to install itself, usually larger stuff w/a few different installers. Give the .exe next to it, msizap a shot after you're done. Anyhow, that's a bummer, good luck fixing it up-James

I had a similar problem with Cygwin a while ago, I didn't really figure out what caused it, but I solved it by moving/deleting the Cygwin installer so it wouldn't be found. Also try searching for the name of the installer (setup.exe?) to see wether it has put itself in some unusual directory, if it has, try renaming, deleting or moving it (first check it is the mp3 surgeon installer!).