I have a Macbook Pro that is a few years old. It's been fine until recently - it shuts off - poof - when I try to play certain games on Facebook, or watch a video on Facebook. I can watch videos fine on a site like YouTube. I thought perhaps it was the browser I was using (Firefox) but it's not. I ran disk Utility and that didn't help. Software Update says I'm up to date. I'm running OS 10.4.11 I'm frustrated!! Any ideas on what to do before I head to the MAC store??