demigod demo freezes computer upon startup

When I run the demo the splash screen will appear, the game will start to load, then my computer will freeze and my monitor stops receiving a signal from my computer.  I have to hard reboot my system from there.

This happens every time I try to load it, my graphic drivers are updated and the game is updated as far as I can tell (impulse tells me its not updated after I verify the install but every time i update it it still says the same thing - v1.10.008 installed).  I have an ATI 5850 so I know I can run this game without any graphical problems so I don't know whats going on here.