Just got home after having rode on my bicycle with my Mac in a bag. Last time I used it, it was drained for battery, but when I got home and plugged the power in and turned it on, it said this weird sound. So I turned it off. Even after it was turned off, it made the sound. Then I unplugged the power and the sound lasted another 5 seconds before it stopped. Then I turned my Mac back on, the sound was gone, but now it seems run a bit slower. I don't know if my Mac has gotten any knocks when it was in my bag. Took this video of the sound just when I had unplugged the power: http://tinypic.com/r/102nw4o/9 Anyone know what this can be? Thanks!