None of the repairs target the media center.
But I did have a user who's media center was crashing and wouldn't even start. Turned out it was a corrupt database file that it uses. It might be worth a shot to try it for yours as well.
On your system go to
C:\ProgramData\Microsoft\eHome
Backup this folder just in case and then delete everything in it. Normally you only need to delete the .db files, but sometimes you need to remove it all. Then see how media center does. You may need to resetup settings in it, but see how a fresh start does.
If it doesnt work then you can put those files back that you backed up
Shane