Do you know what format the music is on these? Use Windows explorer to look for the file name extension. You may have to go to Tools/Folder Options/File Types and uncheck a box that says to hide extensions for known file types. Anyway, sound file players only recognize and work with those that have certain file extension. It may be that iTunes grabbed one it cannot deal with and you have to associate that file with the right player. Off the top of my head, I'll say that Windows Media Player was probably handling those file types. That's fairly easy to fix.
I use Microsoft Explorer XP.....All of a sudden the CD's my friends send me "don't play the sound anymore" yet I get sound on Windows Media.
This as only happened since I downloaded ITunes.?????