It sounds like you might have memory loss. Make sure the internal battery has been changed within the last 4 years. It might need a RAM clear. Follow the Master reset procedure in your programming manual.
If you need a manual, C-tech collective has it here:
http://the-checkout-tech.com/manuals/TOC/cashregisters/Sharp/ER-A320%20programming.TOC.pdf
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Registerman
March 2011