Open the cover where the film runs through the projector. Look into the opening. Use a magnifying glass and flashlight as you look. See if there are any clumps of dust, hair or chunks of old film stuck in the pathway. Debris usually settles near the gear sprockets with the teeth.
Pull out any dust, hair, film pieces or other debris from the projector using tweezers. Turn on the projector and let it run for a few seconds. Check the area again for more debris. Repeat this process several times until the area is clear.
Load the film in the projector following the manufacturer's instructions. Each model loads differently. Turn on the projector. If the clicking sound stopped, you are set. A light sound is normal. You hear the gear sprockets moving the film and the shutter moving inside the projector. If it is still clicking, try the next step.
Remove the film from the projector. Put one drop of machine oil on each side of the gear sprockets right in the center of each one.
Turn on the projector without any film and run it for a minute. This lubricates the gears. Wipe any oil residue away with a cotton swab and load the film. Turn on the projector and watch the movie.