Media Centre not working after sp2

My XP MCE 2004 is not working i.e. My Tv,My Music, My video after I have installed SP2. An audio error message(install MP9 or repair your current instllation) is displayed when I try to play live tv, or recorded tv or music from had disk. My MP9 is working. Even then I have reinstalled it without any result. Do I have to uninstall SP2 for watching TV etc(that was the motive for buying a media centre)? I would like to retain SP2 because otherwise it is very useful in net surfing, security, etc. PLEASE HELP ME TO SOLVE THIS PROBLEM, IF THERE IS ANY SOLUTION OTHER THAN UNINSTALLATION OF SP2.

KUYILATH