Even though you probably don't use Windows Media Player (especially now that you've found J River Media Jukebox and Songbird ) you'll no doubt have those shell extensions every time you right click on a media file. You know the ones. Play this with media player. Add this to media player playlist.
Want to get rid of them? Its this easy
Start > Run > regsvr32 /u wmpshell.dll
Yes. Really.