What version are you trying to run? My laptop is running vista, and I was able to install Civ4 Gold edition fine... It just wouldn't play vanilla or WL. I installed BtS, and I was able to play it just fine. A week later, I tried to play vanilla and WL again, just to see if it would let me, and this time it I was able to. I think you have to install BtS for you to be able play the other versions... I'm not sure, that's just what happened to me...