This may or may not help, but on my F12 pc I had it in hibernation; and when I powered back on it looked like it was coming up then the screen went blank and my monitor came up with 'no signal'. Hmmm, odd.
I tried shift to come out of sleep mode, nothing. Before I rebooted I decided to try to get to a terminal and did ctrl-alt-fn (4 or 5 I think?), and it brought up a terminal window. Then I alt-f1 to get to the desktop and there it was!