ER-4915 - How do I make it work?

We've inherited a Samsung ER-4915 that was purchased new 4 years ago and NEVER turned on or used. We have the manual and quick-demo start up sheet. We've followed the directions perfectly and cannot get the machine to make a sound or do anything. It is like it does not even acknowledge the keys in the keypad (no response no matter what key we press). We've tried all the keys in all the modes and can't even get the cash drawer to open. The digital display lights up and sometimes a PP message appears, but again nothing happens when we press any of the keys. It is like they are not connected or something.