1qaz keys not working on HP laptop

I have read a few of the other posts about keyboards not working but none seem to press on my issue.

I built a friend a new PC about 4 months ago. 3 months ago the 1, q, a and z keys stopped working. She is not exactly computer literate but I had her try replacing the keyboard and the issue continued (I took one of these keyboards and tested it on a separate rig and it worked fine).

I did a reinstall of Windows 7 on the PC. Issue still happens. I tried going into the BIOS to test the keys there They dont even work in the BIOS. What options remain? Motherboard? If the BIOS does not even recognize the letters I am stuck thinking something is wrong with the motherboard.

I cannot think of any other possible reasons and would rather try every last other thing before replacing the M motherboard B.