This thread is old, but i installed the mm7 today and i got the same problem, so i were searching on the internet for fixes, but i fixed it myself
Glad to play it now...
this is what i did
Right click on the mm7.exe -> properties -> compatibility -> run this program in win95 compatibility...
Maybe a bit different because i have dutch names for it so i translated them... hope to helped you with it
Greetz Martijn,