I've seen a lot of people wonder how to run Heroes on Vista 64 online. Some can't get it to run, while others can. THe only suggestion I can think of is to check if all your hardware drivers are updated to run on Vista 64. If not, let me know if updating fixes the problem (or not).
I know what you mean. When I first went to Vista, something as old as X-COM worked perfectly (the copy I had was patched for Win 2000). But a more recent game (forgot which unfortunately) wouldn't want to.
I suggest you keep fiddling with your settings and looking around for more solutions. Failing that, you might want to even consider a dual-OS setup. Sorry I couldn't be of much help.
Whats interesting is i went to a forum dedicated to MM and the Heroes games...and it seems for some reason, IV is just not doable on vista 64 at all. And yea i know what you mean, some old games fire right up...ive got a few that just worked nicely.
Im curious about that dual os setup, whats the deal with that? Also, they have no programs like dosbox for windows games?