How to change BIOS settings on xp?

I need to change the BIOS settings so I can boot the ubuntu os from a usb drive but when I restart the computer the bios screen shows up but it doesn't show a on to press to change settings. I've tried pressing esc and del and all of the F ons..F1, F2 etc. but nothing works. I am using a sony vaio model pcv-7764. Is it too old or something??