There are *lots* of compatibility modes & 3D Video/Sound options. The only advice I could offer is to be completely pedantic about it & make sure you have tested *every* possible combination of compatibility & video/sound options. I know this may not be much help if you say you have already, & I believe you, but there must be at least 16 different combinations I can think of, just off the top of my head. I went through the same thing with MM7 & gave up in frustration, but went back later & tested each one systematically, & lo and behold one worked (that I was sure I had already tested!!).Having since done the same thing with numerous games dating back to Half-Life, I can tell you that most systems will have some combination that will get things going for any game. It's just a matter of finding what twigs for the game & your particular system. Write them all down & go through them all one by one, including changing those registry values for each. I'd be surprised if *something* doesn't work.
I know how annoying it is to have someone suggest something you have already done, but if you haven't systematically tested everything, I would. And after all the fiddling you've already done, it would probably help to start again from scratch with a fresh reinstall. If all else fails, the new Millenium Edition or Platinum Edition (can't remember which) supposedly has XP-friendly versions of MM6-8.
Good luck!!
