That is the sort of thing that can happen when you rush in and wipe everything instead of editing an existing program. You may now have a bit of work ahead of you if you had any special settings before. Have you worked through the setup in the manual? Can you tell me which features are not working correctly?
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If anyone needs a Samsung / Sam4s ER-290 manual, C-tech collective have it here:
http://the-checkout-tech.com/manuals/cashregisters/Samsung_ER-290_operating_programming_manual.html
Registerman, February 2011