Heroes 3 issues under XP or Vista.

can anyone offer some helpful advice on how to solve this problem...? :(

honestly... the only thing that comes to mind is reinstalling Windows.
although... if you're willing, I recommend "treating" it ;) a thorough system cleanup, cleaning and defragmenting the registry can often help. if possible, try running the game on another system to see if it works there.

and one more thing - crashes can be caused by simple overheating. Google it, download some system monitor - check the temperature of the processor/hard drive/video adapter when launching the game.

if you don't want to mess with it - just reinstall the system - if the game's distribution is not corrupted, it should start without problems after that.

by the way, what are your computer specs?