When closing my garage door opener, it will start to close and then go back up. Sometimes as much as 3 times before getting it to close. Is this a sensor problem or what? Should I just replace the opener for $175 or is is less expensive to let the repair guy some at $65 a visit plus parts and repair? Should I just order parts from the repair center and replace on my own (which parts, sensors or what?)

Most doors can easily be unlatched from the opener by pulling a chain. Unlatch it and work it by hand. If it binds where it had been reversing, you need to correct that, or have it done. Post back if you need more details.

Otherwise, it may be a simple 2 minute adjustment you can do yourself. Does the unit have a hole in the back with a nut on it? If so, give it a turn or 2 clockwise. The units have a clutch switch that reverses the door when it hits something. Adjusted too loose, and it reverses like yours, and to tight, it destroys what it hits maybe including people. After tightening it, put something sturdy in the way and see if it reverses. It is also possible the clutch switch is bad and no amount of adjusting will make it work. Mine was. Took me a long time to figure out how it worked, but was a cheap, easy fix.