I overclocked now my computer starts, turns itself off, then starts back up fine

[howdydoody]

Basically what the title says. I have a new computer which I spent about 1300 dollars on. I built it myself and everything ran fine for about 6 months until I tried to overclock it. The bios and overclocking are pretty ***** proof since the motherboard is fairly new. You literally hit one button from normal to overclock. Since then when I boot the computer up the computer comes on for about 3 seconds, the monitor doesn't react at all, then it shuts itself off for another 3 seconds then boots up normally. Any ideas what the problem is or how to fix it? I've seen some similar cases on here but they aren't exactly the same.

 

[Tmagic650]

Yes, turn off overclocking!

 

[howdydoody]

that was one of the first things i did. it still does it =P

 

[Tmagic650]

Reset the bios to the defaults...