Alright, never had this problem in my life, but as soon as I right-click > properties on any music file, it starts playing, which its not supposed to!
But mp3s especially, after the playing is done, I cant bring it over to my burning devices or even edit its id3 tags, it says the file is in use. I restarted my computer about 3 times but the mp3s seem like they are always in use.
Does it show the file properties window as well? Try going to the File Types window (under Tools > Folder Options menu) and find .mp3 files, click on advanced and see if the Properties command has any extra parameters. That’s the only thing I can think of right now.