Can't open windows xp media center?

I have an dell xps with all the latest updates, I tried to open the media center on my system and I get this "Strong name validation failed for embly the file may have been tampered with or it was partially signed but not fully signed with the correct private key" I last used it a month ago and it worked fine, when I downloaded sp3 it screwed up so i uninstalled sp3 and it still will not work. Please help, also i was thinking about just doing a clean install, but I'm concern it will erase my wireless router settings, and help would be nice.