I'm really a novice at PC's my best comprhension is building them. and a bit of GPU over-clocking, what exactly do you mean by that?
I would recommend you reset the CMOS Jumper, it's a little jumper that you move from the default position of 1-2 and place it on 2-3 for 5 - 10 seconds before putting it back it it's default location of 1-2. This resets the bios back to it's stock parameters. This can be found in the motherboard manual however.
Reply when this is done.