It is also possible that your power button is fine and your power button ribbon came loose. If this is the case, simply slide the ribbon back into its slot on the bottom of the power button and then flip the small white flap to keep it in place.
However, you also need to consider the fact that there may be other reasons your laptop won't turn on. If your laptop sustained a fall hard enough to break its power button, there is also a good chance that other components could have also been damaged.