kloosterj wrote:Did you arm the track for recording?
He must have, since the computer keyboard MIDI thing is working.
Do you see the MIDI velocity VU meter going up and down when you press keys on your controller? If not, you might need to check that the controller is being recognized by Ableton, which you can do in preferences -> MIDI. Make sure "track" is enabled for your controller, and when you go back to looking at the track, make sure the track is accepting that controller (or "all inputs"). Like kloosterj said, always make sure the track is armed for recording or has monitoring set to input.
Good luck to you!