Has been there any power outage in the area that you live in? I'm asking this because any unexpected cut off or storm could damage your PC while you sleep.
Anyway, you can try a couple of things and the first one is to unplug the PSU for a while and to press the start button in order to discharge if any electricity has left in the motherboard. Hold the button for about 30 secs., then leave it to plug the power supply unit back in.Try to boot normally.
If that doesn't help, unplug the the PSU again, take out the CMOS battery for some 10 mins. And replace it with a new one if you have. If you don't just plug it back in after 10 mins. and plug the PSU also. Try to boot.
Let me know what happened. Cheers.