OK, I got it,
click on any say for ex: xls document and press shift <key> down and now right click, you will see and option called 'open with' choose that and now brose through the document application list to find excel to open with, below the box you will see 'open all document of this type with from now' Select that and do the same for all document types and you will not get to open ex: excel files in wmc but in excel only and likewise......
Suddenly every time I start any program the Windows Media Center runs. As far as I can tell right now WMC is associated with every program. If I click the icon for Excel, it starts WMC. If I click an Excel file it will open normally.
I cannot activate anything in Control Center because it will run WMC. I can't run any malware apps, either.