Are you saying that you have downloaded .mp3 files and both MusicMatch and Windows Mediaplayer are unable to play them since they consider them to be data? If so, are you sure they are .mp3 files? I have downloaded files with a .mp3 extension and they have been junk. I am not too up with this technology but are there codecs that you have to install in order to decompress certain .mp3 data files correctly (like DivX for some .avi files)? Search for mp3 codecs on google.