Wmp 10 wont play any music or music video files

Need big help, and microsoft is no help, all of a sudden my music and music video files wont play in media player keep getting this message
Windows Media Player cannot play the file. The Player might not support the file type or might not support the codec that was used to compress the file. They played fine weeks ago, Ive tried a system restore, tried the backups, and reinstall media player 10. I transfered one genre of music to my mp3 player and they work fine, but,also they wouldnt play on my other hard drive with windows 7 media player