Telling you it was ready to accept a new code. Since you left it that way it's too possible that someone came by and pressed their remote. Your door now responds to their remote.
Yes, I have some Sears unit from 2000 and just replaced batteries and did the learning steps.
I know this doesn't quite fit in any forum on CNet, but I didn't know where else to go. Every other site has little info about my problem and Sears and Craftsman are useless support companies. My problem started a few days ago. I have a Craftsman 1/2 horsepower garage door opener made in 1999. A few days ago one of my two remotes stopped working. When I replaced the battery, it still didn't work. My other one still worked, so i figured it was just the remote, so I tried reprogramming it using the instructions on the back of the opener. But there was something strange, there was a light blinking in the back that I had never seen before. When i tried to reprogram or do anything, nothing happened and the light just kept blinking. So I decided to call it a night and deal with it later. But then my garage door started going haywire, opening and closing for no reason, sometimes only half way and sometimes redirecting in the middle of opening or closing. I was late for work so I just unplugged the thing and just closed it manually. I have no idea what is wrong with it. I have since plugged it back in and it seems to be ok now, but the strange light is still blinking and I don't know when its going to start opening and closing by itself again, it already did twice tonight. Any help or places where i can get help would be very appreciated.