Sorry not being a Windows person, I might suggest WMP is lacking the appropriate codecs for those types of files - keeping in mind there's many types of mp3 using different copyright techniques of encoding. There's also mp4 (m4a) which is starting to become very popular on the netwk. You definitely need xtra codecs or software for these. May I suggest you try another type of app to burn/convert. Some free ones can be found at: http://www.gnutellaforums.com/showth...threadid=26708 I hope you can fin a solution that way. From memory the link also refers to some converters. most burn software have little problem burning wav/aiff files, but mp3/4 can add a few more complications!