Tools for monitoring file changes in XP?

I have a large-ish MP3 collection (~10,000 files) and recently I discovered that the “last modified” datestamp changed on about 50 of them for no obvious reason. I hadn’t altered them in any way, or even played them during that time.

I want to find out what’s doing this. Are there any tools or utilities to alert me to such changes in a folder tree? There used to be one called FolderMon but it’s old and I’ve heard problems about it with XP, and the company that made it (DiamondCS) is apparently gone.

Any other suggestions? Thanks in advance!