SAME EXACT problems as before.
Sorry to hear that Shook. Yours is a very difficult problem, not simple like everyone was hoping.
You don't want to hear this, but provided that you systematically checked all of the usual issues and eliminated those as possibilities, and that the replacement parts you installed are not also defective (rare, but possible), that leaves you squarely on the motherboard. Yes that means you may have a defective motherboard. The good news is that some defects are just poor settings. I would go to the Gigabyte website (or NewEgg) and read the reviews of your board. You want to know if this is a common issue with that board. For instance, the GA-EP45-UD3L board has a know issue with the onboard LAN and Gigabyte offers a work-around (I am told). I think you would also want to recheck all your previous diagnostics - do them again - real careful.
Resetting the CMOS would be a first step in checking that the MB's settings are not bad. Older MBs had CMOS RAM that was powered by a small battery which could be removed to reset the CMOS. Modern MBs use EEPROM (flash) memory that is physically reset by using a reset jumper or reset switch on the MB. Removing the battery on a modern board only resets the real time clock. But resetting the BIOS is a sure way to purge any bad settings from the BIOS.
If you are going to the trouble of reinstalling W7 anyway, then I would want to be sure that all my BIOS settings were correct, but that would be the time to update the BIOS to the most current version. Also a good time to check your build. Double and triple check all the connections. Also pay close attention to the MB installation: look at the mounting pattern and check for any possible shorts to the mounting stands or case.
Random Ideas - MB related - to try at your own risk:
Try the video card in another PCIe slot if you have one (is the PCIe slot good?).
I just read this this morning, and I doubt this would happen with Gigabyte, but is the PCIe slot "fully wired'? Some boards cheat here and you don't get full bandwidth.
Run with only one stick of memory (Northbridge test).
Disconnect all uneeded peripherals, USB devices (Southbridge test).
*Increase the voltages. WARNING! I have read in another post by
one person that they got system stability by slightly increasing the voltage to the memory past spec. I'm guessing that this would overcome some deficiency on the board. Do not do this until you have read up on overclocking and are comfortable with it.
But in any case I would carefully perform every hardware diagnostic again and double check my BIOS settings before reinstalling the OS.
Good Luck.