Older wrist and pocket watches don't use batteries, but rather are powered by a tension spring that must be wound to retain its strength. Many people with broken watches are under the impression they've overwound the watch and broke it. It's important to remember that overwinding cannot break a watch, so if it isn't working, there is another problem. Watches are designed to wind only to a certain point, meaning something else is the problem.
Attempt to wind the watch again and see if it works. Make sure that the watch was wound properly before you attempt more ambitious repairs, as opening a watch risks breaking it further.
Open the watch to diagnose the problem. Use a knife or thin screwdriver and carefully pry open the cover to see where the problem is within the watch. The two most common problems are the spring not being properly connected and the staff being broken. The staff is easily replaceable and the spring can be reattached to either the winder or the staff. However, do so with caution, as watches can be very delicate and easily broken.
Seek a professional should the problem persist. A pocket watch is a very sophisticated and fragile piece of machinery, so if the problem cannot be diagnosed yourself, it is time to consult a professional. Since many pocket watches are antiques, it might be wise to trust skilled hands rather than trying to teach yourself watch repair.
Remember that a watch cannot break from being overwound. The spring is designed so that it cannot be stretched to a breaking point within the watch. A problem must persist elsewhere. If you open your watch, be careful. The internal workings of a watch are incredibly delicate and precise.
Don't risk removing or repairing parts of the watch if you're not sure what you're doing. In a clock, everything has to be fitted in a certain way to ensure the watch runs correctly. If you are unsure, you will probably need to call in a professional.