I just switched my Core Duo MBP on and went away to leave it to start up, I then came back and noticed it was switched off. So I switched it back on again and it booted straight up, however the entire screen was greyed out (I could see the wall paper, dock etc) and there was a progress bar at the the bottom. I couldn't move the mouse or anything and after a few seconds the entire machine came back to life and off I went. Had it gone in a deep sleep or something? In 2 years of use I've never seen that!