I would unplug the register, take the batteries out and let the register sit for a minute or two. Then follow the steps titled "Initializing the Cash Register" in the manual EXACTLY as they are written. If that doesn't work, the register may be no good. How old is it? Is it still covered by the warranty? You might contact SHARP and see if they can help. BTW, you can always open the drawer to get the money out with the emergency drawer release. Most cash registers have them in one form or another. On yours there is a small metal tab on the bottom of the drawer near the back edge. See "Manually Opening The Drawer" in the manual.
Steve
September 2009