How to fix a keyboard that does not work in Windows 10
We recently had a client with a problem where both his laptop and wireless keyboards stopped working. This can be a real problem, in this case, we were able to use our SOS system and access the laptop remotely because he could still use his mouse.
Firstly we found that in the device manager the keyboard drivers were not working. The error code 19 showed on the keyboard driver, “cannot start this hardware device”.

The laptop had just done a windows update so we knew the root cause. We don’t like to system restore Windows 10 these days as windows will usually duplicate the problem on the next update, so we ran all of the latest updates and optional drivers. We still had the problem.
Removing the drivers from the device manager and reinstalling them failed too.
In the registry we were able to reset a key which helped us get to the bottom of the problem.
Before we go any further, BACKUP YOUR REGISTRY
This registry key: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4d36e96b-e325-11ce-bfc1-08002be10318} is where we fixed it.
We set the default key to a value of keyboard.

We set the UpperFilters to only have kbdclass in it. We removed everything else.

Finally, we had to reset the keyboard in the device manager.
In device manager, right click the keyboard and select Update Driver

Browse my computer for drivers

Pick from a list of available drivers.

Find the standard ps/2 keyboard driver and click Next.

On completion, we restarted the laptop and the keyboard successfully started to work again.
Love you, worked for me 😘