For my part OC fail no post>>>>turn off PSU wait till Mobo goes off.......power up with NO power for 10~20secs..........try powering up with PSU on usually works.

Once I had a major issue had to clr Cmos & battery off..........wouldn't boot: took out G card and unhooked all power to the mobo...........waited for 20mns and rehooked everything reinstalled G card etc: booted to default and resumed OC from saved OC profile

Several things........keep the PCI low if you want to boot back to windows screen easily (100's max)
sometimes the pb is the VGA card and not the OC or Mobo or Ram.

Remember to turn off PSU when nothing else helps.

In cas of high OC fail keep the strp low......1:1 etc