You may be able to find a BIOS upgrade to work around that unhackable, squeaky-clean OEM BIOS with this new guide from Ecoustics. Here's a snip:
If you've got an "OEM system"—one with a recognizable and sustained brand name such as Compaq, Dell, Gateway, HP, IBM, NEC, Sony, or Toshiba—chances are you will not find any parameters worth hacking on—you've got a "dummied down" BIOS.
The unhackable BIOS exists for one very simple reason: the manufacturer wants this PC to work for the broadest, simplest set of PC users. In other words, it does not want to have to bear the cost of support calls related to hacked BIOS settings. Completely understandable if this is a family PC but very frustrating if you're a real techie and wish to experiment.