Ok what it seemed to take was not just a reboot, then running as admin and changing those settings immediately upon reboot, then immediately rebooting again. Well, at least that's what I just did.
Now, those two options, which were at the top of the context menu when audio files were right clicked, have been replaced with a couple of Windows Media Player options, which are still clutter that I never use, but at least they don't have predefined accelerator keys that hijack my ability to use those keys for other items.
Thanks again!