how do i get out of sleep mode

dithedancer

my sons computer as gone in to sleep mode, how does he start it up again. He' s tried powering it back up and putting it into safe mode but nothing comes on to the screen. He as also tried plugging is monitor into another computer it works ok, the processor is making the right noises but all he as got is a black screen.

closed

assuming the video cables are secure and in the correct socket, press the power button, if it doesn't come on after a short press, a long press will switch it off completely - if you've done that already, then it could be a graphics card problem, has it been moved?

how did he put it in safe mode if nothing comes on screen

dithedancer

he didn't put it in safe mode, he tried to, following the advice of some techie expert forum from a few months a go but the person who had the problem didn't reply to say what worked.

closed

has he powered it off completely, by pressing the power button for 6 seconds, and if so, when it is powered back on, nothing comes on screen at all, not even the bios message?

does it have more than one monitor connection on the back?

has it been moved?

make and model of machine?