After doing all the above mentioned steps, I was nearly convinced that the problem could be hardware related, and that I should get the keyboard replaced under warranty. The laptop's volume keys had no problems, the speakers and headphones were all fine. All other keys on it worked perfectly, except for the three multimedia keys. We got it a few weeks ago, and it had been working fine. My HP 100 Wired USB Keyboard is fairly new.

If the volume keys work on the 2nd keyboard, then the other one could be faulty. As a last resort, connect a different keyboard to the computer.Uninstall the keyboard driver (HID), and reboot the computer.Check device manager for potential issues, if there is an exclamation mark that could indicate a problem.Try connecting it to a different USB port.This may sound silly, but have you tried rebooting the computer? This simple step fixes a lot of computer related problems. If you have done all that and are still facing the problem, proceed to the next section. Fn + F11 or F12) for controlling the volume. You may have to use Fn + another key (for e.g. In case of laptops, check if the built-in keyboard works and also verify if the volume keys on it are working.

Do all the other keys on the keyboard work?.If your speaker has a volume wheel or keys, ensure that it is not turned down all the way.Does the volume slider on the system tray change the sound level?.Try plugging in some headphones or a different speaker if possible.Check whether the speaker/sound card that is connected to the computer works.

Computer doesn t recognize keyboard