If this doesn't fix the problem, try the next solution ... connect a different keyboard that works fine on another computer to confirm hardware damage as the cause. While you're waiting for ...

Restarting your Windows computer is a preliminary step ... After that, test and see if you have fixed the problem. Keyboard buttons may fail to work if there is dust or other debris underlying ...

The keyboard fix, which iCulture first spotted, finally puts a line through the mute icon on the MacBook keyboard. The icon ...