Hopefully this is the right room for this question. I bought a SentrySafe -pistol safe- at an auction for a good price. Looks like new. Still in the box. Brought it home. Read directions and installed new batteries. Can not get it to program. Can open with key. Instructions explain how to program a code but do not explain how to wipe a code out and start over. Online instructions are the same as the printed that came with it. HELP!?!