Hi, I'm Pete. Welcome to JustAnswer! I'm reviewing your question now, and will post back with your reply ASAP.
Try the following first and let me know if it works:
Unplug the register for 1 minute, then proceed.Important: This must be done with the batteries taken out of the register!1. Insert the manager (MA) key into the mode switch and turn it to the REG position.2. Insert the plug into the AC outlet. The buzzer will sound three times. 3. The cash register is initialized. The register will display "0.00"4. Re-install the batteries