Sometimes I think my machine is a little too quiet. Even when I'm operating at core temperatures of 50-70 degrees, my Macbook still dosn't seem to think it necessary to activate its onboard fan. Is this normal? I know my fan works because of the next item. Last night I shut down my MacBook after a few hours of fairly intense use (watched a DVD and then was editing and producing audio). It was strange, because after it closed down the fan came on despite the laptop definitely being switched off. Is this normal? It was very bizarre. I tried to press the power button but nothing happned, then the fan switched off and the machine was able to boot as normal. Another problem I've experienced is that when I shut down my MacBook and open it again, sometimes (it's only happned around 3 times thus far) it boots up as though It was asleep, and then just turns itself off. Weird. Any help welcome, should I be worried?