Truncated Registry Key - Cant Open Or Delete It

I have a rather strange registry problem that I can't seem to fix. It's a truncated key in the HKLM/System/Control Sets(all)/Control/Media Categories/ and the key has been truncated ie. {C1j8C09B-11D8-4fa5 and the rest is gone. Regedit can't open or delete it and exporting the category cleans it up but the import still includes it since it can't be deleted. Error message is "Cannot open {C1j8C09B.... Error while opening key." Do you have a method that might accomplish the fix. It's not causing any harm yet since it resides in an area that defines speaker jacks that I don't use but I really want it clean and a reinstall is out of the question with 30 years of custom data and op sys mods.