If you have a Compaq Presario 2100 or Omnibook, or some laptops like this, you can use this program to help you fix the mute key or some other hotkeys. In fact, the program will activate them, then you can assign them to a special task.
You can download the program from here : omke.pl
You may want it to be run everytime your computer starts. To do this, we need to copy the file to /usr/bin, and we need to edit rc.local, in a terminal, type this:
sudo cp omke.pl /usr/bin/ sudo chmod +x /usr/bin/omke.pl sudo vim /etc/rc.local
Then, before the “exit 0”, insert this (Push “i” to insert text, then ESC when you are done):
/usr/bin/omke.pl -k 1
Save (make sure you hit ESC, then type “:wq” to save and quit).
Reboot, and then you can use “xev” to get the keycode or use the shortcut manager to easily set up your hotkeys.