Yesterday I get a call from my friend saying her PB wouldn't turn on, and she didn't know what was up. I went over and looked at it, and it was just stuck on the screen with an apple and the swirly thing. I had to reinstall OS X. It worked fine again, but then I went to download a years worth of updates, and after it automatically restarted, it got stuck again. This is when she realized that she had just updated the night before her computer went bad in the first place. Has anybody else experienced similar issues? PB in question is a 15" Rev D. 1.67Ghz.