that's weird.. bioses have a built-in fail-safe system that would alert you if the voltage is too high and would automatically shut itself down to prevent damages. No beeps? Have you tried using the on-board graphics? or in a graphics card?
The op and myself is not the first people with this model and similar GA-Z77 motherboard to have the failed boot after playing oc.
I've also had the same no post boot black screen problem when I tried F16b bios update.
Flashed bios successfully, reboot to a black screen and no post boot.
Once again, did the force Dual Bios to kick in (sometimes takes a couple of goes to get it to kick in), once recovered I flashed the F15 bios back and no problems.
When I was playing OC and corrupted my bios I got Black screen, no post beeps, could sorta hear a slight muffled click instead of a post beep.
As I said, my only resolve was to force Dual Bios to kick in
(sometimes takes a few goes, but after while you get the timing right it becomes 2nd nature when all else fails):
1. Shut off the power supply using the switch on the back of the PSU, wait 10-15 seconds.
2. Press and hold the case Power On swtich, then while still holding turn on the power supply from the switch on the rear.
3. Still holding the case power on switch, the board will start, once it does release the case power on switch and shut off the power supply via the switch on the rear of the unit. (Do the latter two parts as quickly as you can once the board starts)
4. The board will shut down.
5. Turn the power supply back on using the switch on the rear of the unit.
6. Turn on the motherboard by pressing the case power on button.
Note on step 1:
I actually leave the motherboard on (fans spinning) and turn the PSU off and wait till the psu and motherboard has discharged the power (CPU fan stops spinning).
That's my equivalent of wait for 10-15 seconds.
