Some comfort that others are having problems with garage openers!

I have 2 garages and 2 Sears GDO's. The Sears remote on my truck has 3 buttons and I use 2 of them to open both GD's separately as needed. I am having problems with the detached garage door, which I have linked to the large main button on my remote -- model number for the GDO is Craftman 139.18975 -- 1/2 HP. When I press the large button, it will not open the garage door ( the second button works fine for the other attached garage). The vacation function is not on, so that should not be the problem. The manual function of the door works fine, but it is irratating having to get in and out of my vehicle to put my truck in the garage. It was working fine -- I recently had a contractor paint the garage, so maybe he unplugged it to paint. Thats the only reason I can think of regarding why it changed. I've cleared the programs and reset it numerous times as per instructions on back, but to no avail. The green light on the wall panel remains on constantly. The only thing I notice is the green light on the back of the GDO unit flashes at medium speed intervals constantly( same as one in attached garage -- which works!),but when I push the remote, the light on the back of the unit flashes very fast, however the door still does not open or close. I have to use manual. Grrrrrrrrrrr !

I've spent way to much time fooling around with this and I'm looking for any and all sugestions? Thoughts?

Sorry -- I originally posted this as a followup to someone else's posting -- I'm a newbee :-)

Lorne