hey there, i know this reply is very late haha, im having exactly the same problems, and about the overheating issue, its not my laptop overheating, but the cooler my laptop, the more of a chance i have of my game running hahaha, dont ask why, i havent found any solutions to this yet, my zero hour is on 1.4 or 04, something like that and i have bought it from retail, not cracked either, with no mods, i dont have a solution to this, but im only posting to share my experience and hope that when u find your solution, you can share too.
Personally i would go back to my old computer, its os was vista, but recently the motherboard stopped working and i havent had the money to buy a new one, this current computer is windows 7, and i know for a fact that zero hour isnt working because of the OS, on my vista, i had no problems, and every since getting this laptop, with 7, most of my games have stopped working, or not worked very well at all, i believe it has something to do with its compatibility, games like GTA4 and Fallout 3 aren't working on this computer as they were on my old one, and this laptop could run 20million circles around my old one before the old one would know whats happening its that much more powerful.
but yeah, im here posting to shed some light and hope to find a solution too