Or, since WMP 11 is available for XP, have you tried installing it over the top of your current version?
WMP 10
http://www.microsoft.com/en-us/download/details.aspx?id=20426
WMP 11
http://www.microsoft.com/en-us/download/windows-media-player-details.aspx
Of course, just in case you haven't checked, have you made sure the volume control ON THE MEDIA PLAYER is enabled and turned up?
Hope this helps.
Grif
Have windows" XP 32 " have been playing windows media player 10. Then about a week ago there be no sound. I even updated the player still no action. I have a couple of other players they are working fine. Windows media player have the best visualization

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic