Janice - if they're not traditional wind-up clocks (clockwork mechanism) they will be battery operated - just put a new battery in - AA type usually.
If they are actually clockwork I doubt you'll be able to find the mechanisms you need - a clock repairer (horologist) might help.
If they're battery operated and the electric mechanism has failed - which I doubt very much - Amazon will sell you what you need. Do not worry about the style of the hands they offer - you can use the existing clock hands - they just pull off and are a press-fit.
Good Luck...
May 2016