Hi and welcome to dh
As you are asking about how to Flash A Mobo Bios,it's not difficult but an element of risk in doing so is involved.Flashing a motherboards bios don't give any real performance increases.As you have not said the reason to the bios upgrade.Most bios upgrades only allow a motherboard to install new hardware.
It will help you in a more constructive way to say what motherboard you are using.You will find that there is only 2 or 3 bios manufacturers in the mainstream providers (if im incorrect then im sure more experienced members should answer).
Phoenix Bios is used by many motherboard makers and is probably the most popular.
Who is the motherboard maker IE Asus/Abit etc.
As most makers have a bios flash utility which should do the flash via windows.Most modern motherboards now enable this to be done within the bios setup...
