If the opener was manufactured prior to 1993 it did not come with sensors. It sounds like you may have a combination of problems. I would first check the door springs to make sure one of them isn't broken. Next remove the cover off the motor unit and check the condition of the drive gear. It is white nylon and is just in front of the motor. It should be obvious if it is going bad. On the rear of the motor unit you will find a couple controls. The up and down force adjustments. Increase both of these about 1/4 turn and see if there is any improvement. The normal life of these units is 10 years so you may have a losing cause here. (There are always exceptions though).

Ok i read so many posts but none seem to help me. My garage door opener is a 1/2 hp sears craftsman prt#41A4315-78 that is year (7/95) the sensors have no lit LED lights, but they have been off for at least 2 years. My wall button is just one button (no lock/unlock button) It works (meaning I don't have to hold it down to get it to work) to close and open the garage door. The remote does not. i press it and it won't close the door, the door only move a inch then blinks 10 times, then the main box LEd blinks 4 times, i know that supposedly this is a sensor problem, but if that was the case wouldn't the wall button not work either?

Anytime the main light blinks 10 times and the door reverses to the open position while closing it is a door sensor problem. Nothing else will cause that. You have two clues telling you the sensors are bad. The main light blinking 10 times and the LED with the diagnostic code.