Gigabyte motherboards are actually guaranteed for 3 years from date of manufacture NOT from date of sale.
To check date of manufacture you will need to locate the serial number which is printed on a sticker that is normally attached to the side of the 24 pin ATX power socket on the motherboard or on a label attached to the original box if you still have that.
Sometimes, out of warranty repairs can be done but, of course, there would be costs involved and the best thing to do would be to contact Technical Support to see if they can help you.