how do you flash your bios?
this is a simple/general way.
you find out the type of bios you have (you can see it while its on the bootscreen)
then go to that company's website and download the latest bios and the biosflash utility. you stick the two files on a disk. reboot with a boot disk, and then run the flash utility.
ASUS (that I know, some other manufacturers as well), on it's newer boards, allows you to flash the BIOS within Windows from a file you DL from their site and a program called ASUSUpdate. Epox might, im not sure. Check it out at their website and your manual.