MY QUANTUM 12GB only SHOWS 7GB

[tscc]

I have a Compaq 4880 computer with a Quantum 12GB Bigfoot hard drive. It is only formatting to 7GB and I'm not sure how to set it up in Compaq's CMOS. I've tried using F10 upon bootup but I don't see any setting for the hard drive. Any help would be GREATLY appreciated.

Thanks