Trouble updating BIOS on Gateway E-4600 (c.2001)

Trying to update the BIOS so I can upgrade the CPU to a higher clock P4. I have the BIOS files, but for the life of me I don't see anything in the BIOS menus that will let me update the BIOS. I burned the files to disc (and the boot order prioritizes CD and then floppy before any HDs) but to no avail. Are Gateway BIOSes just really locked down? Am I missing something? Computer is currently on XP SP3.

EDIT: If it matters, the mobo is an Intel D850GB