I run the game on an old desktop PC which has a Win98 partition, and I find it works very well on that. I once tried running it on my old laptop (vintage ca. 1999). The opening scenario ran well, but the game hung when it attempted to load the Sturmford scenario and I never managed to persuade it to get beyond that.
That's rather a pity, because that is the only machine I now have which will run MM6-MM8 as JvC intended them to run. All the peasants (and not just some of them) have names and occupations when you talk to them, and you find the goodies hidden in the pews of the Chapels of the Silver Helm's Castles.
If you can find a copy of Win98 (and I understand that Win2000 also works well) you might try setting up a Win98 partition and running it that way. It won't be perfect, because these games were designed for much slower computers than the ones we have now, but it may be an improvement.
