I'm running Win 7 64 bit, and trying to install the Might & Magic collection. I realize there are still some compatibility issues for some games (not sure if M&M is one of them), but my problem is actually installing the game. It does the file integrity check... then just hangs. Doesn't try to install at all.
Any help?
Edit: Well nevermind :P it FINALLY started running the installer. But took like 5 minutes for it to pop up... so not sure what the deal is with that.
Edit 2: Ok I clicked start installation and it took another good few minutes for it to start doing anything. I had already rebooted my computer and don't have any processes out of the normal running in the background.
Any idea what could make the install so incredibly slow?

Have you tried skipping the check? Alternatively try downloading it again as maybe there is an actual problem regarding file integrity.

Yeah I tried skipping that, did the same thing. It WORKS but as I said in my edits its just painfully slow to start doing anything.
Well games are installed and running fine. I'll have to try and install one of my other games from gog to see if I have the same problem.

Also, consider running the game as administrator (even if you have admin priviledges, you still need to right click and run as admin). It might help, might not - but it's worth a shot. =)

You need to turn off UAC to stop the hang on the integrity check.
I would also suggest installing in a directory outside of Program Files.

You could try temporarily disabling UAC before installing as listed on the Support page :
http://www.gog.com/en/support/might_and_magic_6_limited_edition/The_installer_doesn_t_launch_on_Vista

It can happen with compressed files. Most commonly it will invalidate the entire archive, other times you get major problems and duff files, but access to others. It depends on how it's compressed, I suppose.
It still might be damaged, even if most of the files within seem to work fine. The smallest problem could slow the whole process, even if it's more common for it to invalidate the entire archive.