Garage Door Remotes Don't Work?

My garage door opener can not be closed or open with either the portable or keypad remotes. The problem is intermittent and it fails most of the time. I have removed the fluorescent light. I also cleaned the control board with electrical cleaning solvent. The direct opener button works fine.

By the way, how do I open the keypad on the keypad remote? I'm able to unscrew the bottom screw to the wall, but the top one requires removing the keypad to access the screw.

Thanks for any advice.