Hi. I've got a late 2008 mb pro running latest version of 10.8. I stepped away for a few minutes when I came back the screen was flickering I many colors. On reboot it stays black, but you can hear the hard disk cycle and the white light in front lights up. The caps lock button works. It seems the computer itself minus the screen is functional. I tried the usual tricks, pram, safe mode, unplugging, pulling the battery, but the screen stays black. Any suggestions? I have an appointment tomorrow to get it looked at. Many thanks. UPDATE--I let it rest for ten minutes then started up again. The screen was grayish with rainbow lines running vertically on three places, as in attached photo.