I would think that entering and exiting installer mode would force the panel into checking the status of it's backup battery,if you get no response from the keypad no1(wired), then maybe the control backup battery needs replacing.
As gts has said your keypad will be showing the red ring, try pressing the "tick" button twice, but if you can't get to read the alerts because the keypad is unresponsive,then replacing the backup battery is a good place to start,especially if you don't have the correct equipment to test it.
Just throwing an idea in gts :-)
e manno, October 2012