Hi guys, this is my first post on this forum and I am a complete beginner with linux so sorry in advance if I am slow on the uptake.

My problem is that I want to reinstall Ubuntu 13.10 from a bootable USB, which I've got following these instructions, but I cannot get to the BIOS to boot it as grub keeps loading first. I've tried hitting F12 to access it but it won't work. I've also tried navigating to the BIOS from grub command line but I have no idea how to do that.