The blinking 4 times every 3 or 4 seconds is the code for sensors mis-aligned but that would not cause the symptomes you describe. Is your door stuck in the open position? Check to see if that blinking light is blinking 5 times instead of 4. If not, the most common thing for lightning to get to is the logic board.

Hi Don;
Thank you for your quick reply.
I 've disconnected the door so that's not the problem. It seems that the indicator light blinks 5 times every 3-4 seconds, and I hear a click coming from somewhere inside the unit. I've removed the covers from the unit and everything "looks" ok, but I'm no electrician. What do you think? I can probably start by replacing the logic board?

No logic board yet. I misled you when I asked if your door was stuck in the open position. It is the trolley you need to look at. That is the thing the chain and the door is connected to. If it is jammed against the bolt in front of the motor unit it will cause the symptom you have. If it is, remove the bolt and then operate the door. With the door closed locate the 'up limit' on the side of the motor unit. Using a small screwdriver turn this control about 3 turns in the opposite direction of the arrow printed on the motor cover. This should end your problem. Be sure to replace that bolt.

I should have mentioned in my last follow-up that I have disconnnected the garage door opener completely. It sits on my workbench in the garage and I still get the same result mentioned earlier when I press the remote. This problem occured after a thunderstorm so something inside the unit has suffered some kind of electrical damage. Before the storm everything worked perfectly.

Make sure the sensors are aligned. If they are okay, then disconnect the wires to the sensors and then reconnect them. After a storm, they sometimes need to be reset manually.