The door that won't open, or opens a few inches and stops, is the one we hear about most from homes in this part of the service area, and on a door built after the late 1990s, that's usually a torsion spring that's finally given out after years of carrying the weight of a full steel sectional door. You might hear a bang from the garage days or weeks before it happens, that's the spring letting go. A door that reverses halfway down, or won't respond to the remote at all, points more toward the opener itself, the kind of circuit board failure that shows up once a unit is into its second decade. Either way, don't keep hitting the button. Running an opener against a broken spring strains the motor and can bend track.