Have you tried plugging in an external keyboard just to determine whether the issue is limited to the internal keyboard or whether all keyboard input devices don't work?
Also, did the BIOS flash indicate it applied successfully? Even if it did, you could try applying it again. If that doesn't work, you should be able to get the older version from HPs support website, but I'd only install the older version if you cannot resolve the issue with the latest BIOS.
P.S. By the way, and apropos of nothing related to your technical issue, that's a fascinating avatar. Very Escher-esque.
Edited by britechguy, 10 August 2017 - 09:39 AM.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story