So the first thing people do when their cash register is stuck min an error or unknown state is unplug it. Please don't unplug your cash register unless a technician who knows that register has instructed you to. You can make the problem worse when you unplug the machine.
Cash registers all have a rechargeable battery in them. The battery is only used when you lose power. If you have an older register your battery may be dead and you don't even know it. If you unplug your register with a dead battery you will have just made the problem so much worse.
If your register is stuck no amount of unplugging it will help. If the battery is good you can leave it unplugged for hours or days and when you plug it back in you will be right where you where when you unplugged it!
If you need help trouble shooting a SAM4s or commercial grade Sharp cash register we do help for a fee, if you bought the register from us we can help for no cost. Call us at 1-800-863-2274