This just happened today when I was playing a game of RCT 3. The display on my "15 1.67 ghz PB started turning off. I wondered what was happening, so I quit the game after I got the display back up and discovered my computer had gone into sleep mode, as it was asking me to type in my name/password to bring the computer out of screen saver. I decided that I would leave it alone and tackle the problem after I got back from class. I got back and tried to wake my computer up, and got an even weirder situation. The screen would come on, but the backlight wouldn't. (This is an issue that my dad dealt with his older "15 PB.) I thought, "Here I go, I need to send this in to Apple..." when the computer seemed to go back to sleep, and wouldn't wake up. I restarted the computer, and the screen came back on, and let me use the computer for about 20 minutes before the display went kaput again. I force restarted the computer again, and now the screen goes blank before I can even log in. I was able to log in once, but that lasted only a few minutes before the screen disappeared. Solutions?