How about this program: http://www.videoconverterfactory.com/tips/mp4-to-avi.html
It can do many video to audio and audio to video conversion including MP4
MPC-HC is good one, and you can try it. To fix any player playing problems, you're free to try this one
http://www.videoconverterfactory.com/tips/windows-media-player-not-playing-dvd.html