This is a start. This gave me your Motherboard Manufacturer. You need to find the actual Part number of the motherboard.
Here is the link the company's website
http://www.giga-byte.com/
Here is the link to your Manufacturer's support page where you can select the part number of your motherboard to download the drivers
http://www.giga-byte.com/support/support.htm
You need this number to figure out which board it actually is. The easiest way may be to take the cover off of your computer, then read it off the motherboard. From example part numbers on their website, your part number should start with "GA".