I have a macbook with Snow leopard and I recently started having issues. Last week I closed my mac as usual, but this time when I opened it up the screen was black, meaning no power. I pressed the power button repeatedly but would not work. Then I took the battery out and replaced. After about 40 minutes the screen came back on, but it this time it said to "power off and restart." I did, however it made me do this about ten times then powered off again. Luckily after pressing keys and the power button out of panic it worked and everything came back on. I closed my mac by habit when I was done and it did it again! Now I am afraid to turn off my mac. : ( What is up with this???