On Asus motherboards, usually you hit F7 to change from "EZ mode." Before you decide to update to a new BIOS, you'll need to know which version number you have so you can check it against the list of available updates to see if they are actually newer. You may also decide when looking at the change logs, that you don't need to update at all. To find the correct BIOS update, get the computer product name...
