Originally Posted by JustinBoSc
I may be wrong about this but I believe some MOBOs have to have a fan plugged into the CPU fan plug to post. You said you have an aftermarket CPU cooler, do you also have a fan speed controller?
EDIT: I recently removed my GPU to make sure it wasn't causing an issue and I had to reboot 2 or 3 times before the onboard video decided to work. When it finally did it took about a minute before my monitor actually got the signal. Just a thought.
Most of what you said is correct, however with Intel LGA 1156/1155 whenever I have my gigabyte go down with core i3 540..
I normally, switch down everything, turn off the psu little black switch and let it for about 8 minutes.
Come back to it again, and make note of your keyboards led, 3 flashes means normal post.
Two flashes and then it goes out means there is a bios error.
If push comes to shove he will need to reset the cmos with the little black jumper.
That will take less then 3 minutes to get it working and change some settings.
If he does all of this and it still fails, I'm leaving you in charge to get the "asus technical support number and intel rma support page and direct contact number.
You never which part may be at fault, normally it is the motherboard at times we see here and at other technical support forums.