Windows7 mediacenter taken over machine

After an update the Win7 media center has taken over all the files changed icons and blocks IE. Everything opens with WMC if you disable nothing runs. You get this message:

Windows Media Center

Windows cannot open this program because of a software restriction.

I can't access it to change anything

This is awful I can't even use the disc to repair because like everything it opens in WMC and can't run.

thanks guys I really need your help on this one.

patrick