What settings would it be under BIOS? For Asus laptops, the action keys are a software function rather than BIOS, so I'm a bit surprised it isn't the same thing for HP as well.
In the BIOs, there's an option that says "action keys" with the option to disable it. It comes enabled stocked. When you disable it, you use fn+f1-12 to raise/lower volume and brightness.
I forget under which tab it falls under since I had to exchange my HP laptop. However, it will be here on Thursday =)