Wow you saved me from so much 'update' distress. Indeed I had done a similar thing somewhere in my distant memory. Simply deleting my hacked registry key entry as shown below solved my problem.
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout]
"Scancode Map"=hex:00,00,00,00,00,00,00,00,02,00,00,2a,00,3a,00,00,00,00,00,00