Twice in the past day, I've put my macbook to sleep for a minute or two, carried it somewhere, then when I open te screen back up, it doesn't turn on. Even if I press the keys it won't turn on. Do you have to press the power button or anything? The reason I said that I carried it somewhere, and then tried to awaken it from sleep is that maybe by carrying it, the hd shuts down because of the sensor? However, I carried it somewhere just then and it DID turn on when I tried to awaken it, so I don't know.... Any help? Thanks.