You said earlier that your RAM, CPU and video card are all working fine, and it can't be the motherboard. That leaves you with the PSU. Try to check the PSU in another comp, i know it's not easy, lot's of wires, but give it a try. If it's not a quality PSU, I wouldn't be surprised if it is the culprit.
Now you said you were gonna send "it" back. What is "it"? If it's the cpu, I'm sure overclocking voids the warranty (or is that only for Intel), so I don't know how this would work. Is your heatsink/fan working? Try removing it and then check the cpu, anything unusual (smell, discoloration etc), and then reinstall the hsf. Let's see if this works.