Hello. My name is Michael. I can assist you with your question.
You didn't mention the model number of your camera, so if you reply, please include that, as well as any additional information you have that might narrow things down., The first thing I would suggest doing is using compressed air to physically clean around the switch and try again. If that doesn't work, you can safely use WD40 to lubricate the area and clean the contacts. Temporarily, you should be able to remove the battery to turn it off.