We have multiple reports that an update to Windows 7/8/10 has brought problems with MoHAA. Some people cannot open the game anymore even if they try to run it as Administrator. People in our community have found out, that it is an issue with the game CD keys. Hence it suffices to use a NO-CD crack of the game.
You can download a properly working exe to your game here:
MoHAA: http://mohaas.net/web/res/game/MOHAA.exe
Spearhead: http://mohaas.net/web/res/game/moh_spearhead.exe
Breakthrough: http://mohaas.net/web/res/game/moh_Breakthrough.exe