I have a big security problem with my Sears Craftsman 1/2 HP garage door opener. I lost one of the remote (probably near my house) and I re-coded the one that I had, hoping that the other lost one would be useless. This is not so unfortunately. Is there anyone who can tell me how to make the lost remote useless? I have another garage door opener with two remotes and I can't just change a code on one remote. Because they are the same frequency, only one has to be programmed. I have Green LCD on the back for programming a code, made in 1999.

Erasing codes