Howtogeek posted a guide about reinstalling Windows Media Player in Windows 7

If you're having problems with media playback on your Windows 7 PC using Windows Media Player, or even using other applications like Media Monkey, you might need to reinstall Windows Media Player. But how? Reader Ted wrote in with this tip, which solved his problem of playing ripped music files in either Windows Media Player or Media Monkey.

Step 1: Uninstall Windows Media Player
Open up Control Panel and type ?windows features? into the search box, and then click on Turn Windows features on or off.

  How to Reinstall Windows Media Player in Windows 7 to Solve Problems