Restore settings in MS Media Player 10?

[crgkma]

I have been ripping my cd's to mp3 in Media Player 10. During the ripping process, one can usually listen to the songs as they rip/convert to mp3 format. This has been working beautifully, no problems. However, I recently noticed that the last 4 cds I ripped don't have any sound. They show up in the library but when I try to play them, they are silent. I don't know what I might have done to mess up the settings. Has anyone got any fixes/ideas about this situation? Is there a way to restore the original MP10 settings?