|Check the revision number printed on the motherboard, then go to the Gigabyte support site, select that revision (ie:rev 1.2, etc.) number and then check the CPU support list. In the right column is the BIOS version that supports each CPU. If you have an early revision of the board, you may need to use an earlier (supported) CPU temporarily and update the BIOS to a version that supports your CPU.|
Make sure that you plug the CPU heat sink fan into the CPU_Fan port. Many motherboards will not boot up without the CPU fan plugged in.
What type of heat sink do you have? How did you apply the thermal compound (except on stock heat sink with preapplied compound)?
Please include all specs on the power supply.
Try built in video with the video card removed.
Pull the entire thing apart and bench test it the right way.
You have to be a little bit crazy to keep you from going insane.