computer won't start up
While I was at my computer (MBP late 2011) this afternoon, the screen went black. The computer had turned off. I restarted the computer and the white screen came up with the Apple logo. Then the wheel/gear began to spin. This went on a long time, then the wheel/gear and logo disappeared, leaving the white screen. After some minutes, the screen went black.
I tried to start up in Safe Mode, but there is no chime when my computer starts up. Any, after several tries, exactly the same things as above happened.
I have a keynote talk stuck in this computer I have to give in two days.
OS X Mavericks (10.9)