Refer Pureboot - How do I see the OS Boot Menus? - #5 by kieran ?
This seems a bit design-buggy. With most BIOSes, since you can’t be sure exactly when to press the key, and you don’t get absolutely immediate feedback that pressing the key has worked, whatever key is used to bash on in order to get into BIOS (/ or boot disk menu), must have no meaning within the BIOS (/ or boot disk menu).
This contrasts with, say, the GRUB menu, where you have exact feedback on the screen as to what’s going on, what to press, etc. - assuming that you choose, as I do, always to display the GRUB menu (for X seconds).
‘Del’ for the BIOS is pretty standard. The boot disk menu may not be. I have three computers here encompassing three different keys (each of them an Fx key) to get into the boot disk menu. How’s that for poor standardisation?