I'm not a fan of Asus and won't be buying another because of having to fight Asus over a bogus warranty denial (it's a long story but they only replied about how to RMA my unit weeks later on the EXACT day the warranty expired).
Anyway, it's just a matter of hitting F9 to do this, there's no need to worry about booting from USB or CD (unless of course you want a different OS eg. Windows XP Pro, Vista/7, or a flavor of Linux or Unix). Also remember that you need to fully/properl........