SP2 problem in XP MCE 2004

I have recently updated my XP MCE 2004 with SP2 via the auto update route. Installation was smooth and everything is ok. Previously I had some problems with Norton Internet Security blocking websites. Windows security centre removed this problem. But my relief was temporary. Suddenly I found that I could no longer operate my media centre i.e. My Music, My Tv, My Video etc.are not working . Instead, an 'AUDIO ERROR' MESSAGE IS DISPLAYED, asking for reinstallation of MP9 or repair your current installation'. Even after 'reinstalling' a 'working MP9' the same message is displayed. Then I found out SP2 is the CUASE. Anybody CAN HELP ME ? IS THERE ANY SOLUTION other than uninstallation of SP2 by system restore or removal? Please advise. I would very much like to retain SP2 because it is very useful otherwise. But I purchased this MCE 2004 for watching tv, as a second tv in my home. But I am not able to watch tv in my computer.