As for running on WinXP, there are ways -Disable harware sound and graphics and switch to software in the games' configuration utility ....
If that does not work, then try running it in compatibility mode for Win 98 (I know its XP but this works) and make your own shortcut to MM7.exe on the desktop. Use that instead of the one you most likely put during installation ....
Also try running it in Windowed Mode if all of the above don't work.
This site might have multiple copies of M&M Millenium edition!!