cant play, why?

I have three computers that this game is installed on, my main computer is an AMD 64 4000, 2gigs ram, X-FI sound card, Nvidia Geforce 7950GX2, I can load the game but as soon as I click on anything it restarts my computer and I get an device driver error. This computer was built to game on, all drivers are good and system is VERY stable, this is the only application that crashes my computer and gives me this message. My second computer is a Toshiba laptop Intel P4 Mobile, 1 gig ram, Nvidia Geforce Go 460. The game plays but every so often I will go into a screen like research and it will be distorted, but slightly readable, and its not always the same screen or every time. My last computer is an Acer laptop with an AMD Turion X2, 2 gigs ram, ATI Radeon Xpress 1100. The games plays wonderful on this laptop with no problems or hitches. What is going on? I have tried to reinstall the game on my main machine but that did not work. The way I get this game is through steam. All computers are running Xp Pro SP2 I am not your average computer user as I work for Time Warner Telecommunication as a Hardware Technician, so I know what I am doing. Thanks for the help, Andrew