As Nmsuk suggests you need to boot into the motherboards 'flashing utility'. Now the instructions on how to do this with each motherboard can be slightly different. If you check the page from where you downloaded the bios there should be a 'How to flash the Bios' link somewhere.. I looked to see if I could find your motherboard make but didn't find if you had posted it or not.. Would you mind posting again as I can help you further once I know the name...