Before we suggest the OP runs out and buys a new keyboard, there are a few things to try with the old.
I never said there was a setting to turn those keys off.
Also after re-reading the original post, I missed the word "replacement" and instead was thinking you bought a USB keyboard from HP. After seeing this, then my previous post is basically null and void. Instead try using a USB keyboard (as suggested) and see if it works - though the brand is really indifferent and it can just be one borrowed from another computer. I assume that since it's a laptop, you carry it around with you and keeping a full size keyboard with it is not very practical.
If the USB keyboard works, then there is likely a hardware issue on the system board.