I have an ASUS laptop model U47A with an unusual keyboard problem.
After rebooting, it will not accept input from the keyboard. But it does seem to recognize the Caps Lock key (because the "Caps Lock on" indicator comes up on the Windows 10 log in screen). It will also recognize the Enter key to tell me that the lack of a password is the incorrect password.
To troubleshoot, I tried a USB keyboard and restarted. Exact same thing (Caps and Enter are recognized but not the other keys).
Next, I opened up the laptop and reset the three flat cable connectors running from the keyboard to the main part.
I was tempted to believe the keyboard just needed to be replaced until I was getting the same behavior from the external keyboard (which I know works with another desktop box).
The laptop runs Windows 10 Pro, 8GB Ram and a second (I think) gen i7 processor (if any of that matters).