Hi,
thank you for the information although it would help me further if you could post the make of your graphics card.
As Windows 8 is a new operating system it is extremely important to be running with the latest drivers and bios. This utility will enable you to flash the bios:
@BIOS
You must follow the instructions to the letter and if your unsure of anything then post back and I'll guide you through it. Gigabyte boards are blessed with a back up bios or dual bios so flashing isn't as risky as with other boards. Get it wrong and the back up bios will kick in.
Your motherboards website is here:
Link Removed
Make sure that you have the correct board version, either 1.1 or 1.0. You can find out which one you have by actually looking at your motherboard inside the case. It's usually printed on the board around the edge.
You can also use the drivers listed under windows 8. They might not actually be the latest but better than nothing.