I'm on a black 2 ghz Macbook with 2 gb of ram, and I purchased OB via steam. First time I ran portal, it ran completely fine for 3 or so minutes, and a blue error screen came up and my computer crashed. Now whenever I run Portal it closes after loading. Next I tried TF2, ran fine (with some graphical errors) for 5 or so minutes, and then it came up to the same blue screen causing my computer to crash, and TF2 not being able to work properly afterwards. Same deal with Ep 2. What the hell is happening? I've uninstalled and reinstalled the games multiple times and I've reinstalled Steam, no dice.