Sorry to be late to the topic but I notice no one has recommended the user rename his eHome folder (typically C:\ProgramData\Microsoft\eHome). That folder contains all the MC files. If you rename this folder, Media Center will see it as a new install and start the process anew.
If it doesn't let you rename the folder, you may have to stop the Windows Media Center Receiver and Scheduler services (see control panel, administrative tools, services).
If it doesn't let you rename the folder, you may have to stop the Windows Media Center Receiver and Scheduler services (see control panel, administrative tools, services).