I let my 1.5GHz Powerbook sit in my office on my desk and when I come back in the room sometimes the screen is just black, but I can tell it is on. When I hold down the power key, the PB turns off and starts up fine. I recently added a Bluetake bluetooth mouse, but this also happened before that. This has happened to me twice in the past day and I added the mouse on Friday. I have no clue what this is and it is making me very angry because this is very "Window-esque" and that is the whole reason I switched. Does anyone have a clue as to what it could be and what I can do the next time I encounter the situation?