beta bios's wont be on gigabytes site
heres the latest beta bios for the x79 up4
http://www.mediafire.com/?8j3clrhotzgvx9c f3t beta
to update bios you need a usb stick formatted to fat32,extract the files from the above and put them on the memory stick,bootup pc with stick plugged in and press end at gigabyte splash screen to enter qflash,then follow onscreen guide and update the bios
remember,flashing the bios will rset any oc/bios settings so make a note of them beforehand or take screenshots with usb stick installed and press f12 for each bios page
for a blind flash with no gpu installed you could try pressing end then enter and enter again with just the memory stick and bios attached
EDIT: also try with dvi/vga/hdmi cables if your monitor supports them,chances are it will display a picture on one/all of those three ports