If you have multiple media players such as Windows Media Player, WinAmp, QuickTime, RealPlayer, etc on your system, you may like to control which launches when you want to play a particular type of file for example audio files (mp3) as against video files (avi).

The way to go about it is to set file associations in the various players. But I suggest you de-select the file type in the program it currently launches before selecting it in the one you want. In Windows Media Player 11, for instance, select Tools > Options > File Types tab. Uncheck (if you do not want Windows Media Player to play) or check (if you do) such options as mp3.