Well Melissa, you have about a hundred parts or more in the watch. If anyone of them is dirty, broken or whatever your watch will not run. You need to go talk with a watchmaker (not a jeweler) about your watch. If your watch hasn't been "overhauled" in the last ten years then that is most likely what is indicated. Watch oils and greases evaporate or turn to a scummy mess which may be the problem. Or you may have a broken balance staff. Or you may have rust and dirt built up to the point the watch can't overcome it.