We have a ceiling fan with a light but no remote. The room was not wired for a fan so we had hd install a switch on the wall to turn on the fan and light. Sometimes the light will come on with anyone being in the room. Most of the time it is the one room although we have had fan w/lights installed in 3 different rooms. We have changed the batteries in the switch, but did no good. The switch is wireless because the room was not wired for fans. How can we stop the light from coming on by itself?

Try changing codes in case neighbor is on same code/freq?

Yes, you will need to change the frequency of the switch and receiver:

Ceiling fan remote controls - help and FAQ- Ceiling Fans N More (http://www.ceiling-fans-n-more.com/ceiling-fan-remote-controls.php)