Windows Media Player places its context menu entries in a way that even ShellMenuView cannot disable them. However they can be removed easily.

Go to Control Panel > Default Programs > Set Program Access and Computer Defaults. Check the “Custom” options and click the little arrows at the far right side.

Scroll down the menu that appears until you see the “default media player” options. At the Windows Media Player part of this section remove the checkmark from the option “Enable access to this program.”

That’s it, WMP context menu entries are now removed, and they can be added again by checking this “enable” option whenever you want. Of course the Player can still be used, even as the default player of your PC. Enjoy!