I have a sony vaio that originally came with windows 7

managed to grab a copy of windows 8 and i absolutely hate it. So ive decided to reinstall 7 from a bootable usb...

Cannot access the bios no matter what! There is no UEFI option under the advanced settings anywhere, holding down the shift key while restarting doesnt work and pressing the f12 or whichever one it is at the startup screen does nothing...

any other ideas?