1
The solution may depend on your keyboard, try each of the following keyboard shortcuts one at a time to see if the Windows kwey is working correctly.
Fn + A
Fn + S
Fn + Spacebar for 3 seconds
Tap the Windows key twice
2
If none of those work for you:
Open Device Manager
Expand the Keyboards section
Right click your keyboard and choose 'Uninstall'
Then restart (not shut down) your PC