Dear Customer,
Thanks for your feedback. Would you please try the troubleshooter? Maybe it can find your Media Player's root cause and solve issue. Please attempt try it. The location at http://support.microsoft.com/mats/windows_media_player_diagnostic/ or http://support.microsoft.com/mats/no_sound/. Hope it will helps.
Please Mark as Answered If this is helpful Or Un-Mark as Answered if it is not helpful.
Best Regards, Alex