Remap Caps Lock key to 'Run Command' (Alt+F2)

1. Install Xdotool and CompizConfig Settings Manager from Ubuntu Software Center

2. Disable Caps-Lock by opening Keyboard Preferences

   System ▸ Preferences ▸ Keyboard

   Goto tab Layouts then click the button Options...

   Change the key behaviour to CapsLock is disabled

   

3. Open CompizConfig Settings Manager

   • Use Run Command, Alt + F2, and type ccsm

4. Enable Commands plugin then add the following

   • Add xdotool key alt+F2 to the first available command slot

   • Goto 'Key Bindings' tab. In the same slot number assign Caps Lock key.

     Note: It will show VoidSymbol as the button assigned but this is fine.

     

     

Going by what you mention here. You can disable CAPS LOCK by going to System ▸ Preferences ▸ Keyboard. Then in the window that opens Layouts ▸ Options.... Here you can change the CapsLock key behaviour and disable it.