Updating your BIOS has nothing to do with your Operating System. You can consult your Motherboard manual, or website. They should give you detailed; step by step directions on how to do it. I know ASUS has a utility that allows you to plug your Flash Drive into the motherboard and touch a button on the motherboard to automatically update the bios.
And I can almost guarantee that updating the BIOS will set it back to default settings.