RollerCoasterTycoon-dm locks up my PC

I downloaded the "RollerCoasterTycoon-dm.exe" demo file and each time I use it after about 2 minutes it locks up my Laptop. I am running Windows 7 Home ver. But it set up as compatibility = XP. About 4 years ago I had the CD and really enjoyed the game, and would like to play it again. Can someone help me please?