This problem really puzzle me. I installed ubuntu 11.10 for a friend on a new desktop computer with an asus P8H61-M LE motherboard.
Everything went fine (no EFI related problem apparently), ubuntu seemed to work flawlessly... Then foolishly I tried to hibernate the computer instead of shutting it down.

Now the computer won't get out of sleep mode. It seems there's no video signal anymore, : the screen remains black when I start the computer, I can't even see the bios options.

Though when I press the reboot keys after a while (ctrl+alt+shift+B), I can hear the system rebooting, so it seems everything is working but the integrated graphic cheap, who seems to remain in sleep mode.

I tried to reset the bios with jumpers, removed the battery even, but it didn't change anything... I have really no idea what to do now.

Help !