I moved my pb from my desk to my lap and it the hd or fan or something made a whirring/buzzing noise. and it would come and go as the laptop is being tilted 30 degrees or so. Kind of like how if a fly comes near you ear and leaves real quick you get a buzz noise. It only makes the noise when you move the laptop. It's not like I was jerking it fast either. Slow dip of it and you get the noise. weird. what is it?! It's never done this before, should I be worried? I don't have applecare and warranty is gone. Plus I'm studying abroad in France in less than a week. I'll need my computer to be in working shape.