Hello Everyone,here is my dilema

first a little info of my system

PC, I7 950 not overclocked running at 3ghz, GTX460 1g, 4gig ram, Win7 32 bit all updates done, Latest drivers including the new nvidia beta driver.

I have the game on high settings with no problems it runs smooth, But when I enter the dragon lair that is behind a shack after i loot the bodies and killed the wolf there and I take a step to go forward the game shutdown and takes me back to the desktop.
My pc runs BF3, MW3 and Crysis 2 on ultra with no problems, I don't have heat issues at all. I read here that if I disconnect Steam Friends updates would help correct the issue but no luck, anyone can help?