... it's just that you've obviously done your research and already tried almost everything that we'd suggest. It's also obvious that Ubisoft doesn't care a bit about the M&M RPG fans or franchise, otherwise they would have fixed the multiple problems with the game on older systems.
There are two things that I can suggest you look into. If you've previous installed the game, uninstalled and re-installed in a new location, then there might be old registry entries that are confusing the game. You would need to find and remover those manually. Yuck.
The other suggestion would be to run the game from a FAT32 partition if you're not already. Inasmuch as you would need to uninstall the game in the process, scan the registry after doing so to avoid leaving artifacts.
Best of luck. Please let us know what you try and what (if anything) works.