Hi, welcome to TSF.
Are the "lost" files on a separate partition (not the XP drive)?
See if you can recover the files with these programs:
Recuva
Roadkil's Unstoppable Copier
I don't know how the files got deleted. "MP3-eating" viruses is an urban legend, AFAIK.
"Only" worms??? Sure doesn't sound like your computer is clean.
I think you should follow these 5 steps:
http://www.techsupportforum.com/secu...oval-help.html