Driver 9.4.156.0 for the Microsoft Digital Media Keyboard 3000 doesn't support the volume up, volume down and mute buttons.
They are unresponsive in OS and applications.

On windows 8 on the same machine they work fine, but after upgrading to 8.1 they become unresponsive.

I tried a rollback, and the same driver worked again for those keys. Now back on 8.1 and unresponsive again.

Hi,

In the link below about Digital Media Keyboard 3000 driver download, it doesnt contains Windows 8.1 driver.

http://www.microsoft.com/hardware/en-us/d/digital-media-keyboard-3000

You may need to contact Microsoft Hardware support for more help.

http://www.microsoft.com/hardware/en-us/support