Hmm, is it grayed out so you can't choose any functions? Try upgrading by clicking help > check for updates to see if you have all the latest updates do this too with windows update Start menu > 'type' windows update in the search bar & see if that works. If not try this. It might have some weird bug that doing a clean install would work.
Click on Start button, and open Control Panel -> Programs -> Programs and Features.
Click on Turn Windows features on or off in the left panel.
Expand Media Features.
Uncheck (untick) check box for Windows Media Player.
Click Yes to continue when prompted with dialog box saying:
The following Windows features will also be turned off because they are dependent on Windows Media Player. Do you want to continue?
Click OK to remove WMP and WMC, and quit.
To re-install Windows Media Player and/or Windows Media Center again, follow these steps:
Open Turn Windows features on or off again.
Check (tick) the checkbox for Windows Media Player and/or Windows Media Center.
Windows Media Player 12 will be reinstate and reset. Launch Windows Media Player, and re-initialize the program.
Tip: If for some reason the re-installation of WMP and WMC is not clean, once uninstalled, try go to %ProgramFiles% (and %ProgramFiles(x86)% for 64-bit OS) folder, and delete the Windows Media Player folder.
Another option is to download CCleaner http://www.piriform.com/ccleaner/download there's an option to clean windows media player files and do a scan on your registry with it, just save a copy of your registry files before deleting any of them with CCleaner.