Few days ago I was trying to fix my friend’s laptop but for some reason I couldn’t use the keyboard & I thought if I can use the external keyboard then it might work but it still didn’t work so after some tweaks I discovered that the problem was in Windows 10 itself.
Here how to fix it:
Go to Control Panel from the Start menu or from the search box in Windows 10 as shown below.
Now click on Ease of Access Center as shown below.
Now click on Make the keyboard easier to use option as shown below.
Clear the Turn on Filter Keys checkbox as shown below.
Now restart the computer & this should fix the Keyboard not working after login issue.