If My Cats Paws Turned Black What Should I Do/?

I would take her to a vet, she might need antibiotics or something. A lot of times I have seen skin on an animal (or if you think about it people too) darken or change pigmentaion when some sort of trauma has occurred. But, I would have a vet take a peek, b/c cats are prone to get abscesses. Also, cats are very tough and if they favor a limb it usually means they are in a decent amount of pain/discomfort. As a side note DO NOT ever give a cat over the counter meds (unless directed by a vet) b/c you run the risk of causing all kinds of health problems.

Odd, normally the pads of the paws are black. If you mean the whole foot is black, then you need to get the cat to the vet, this isn't natural. Hope this helps, good luck to you.

This cat needs to be examined by a veterinarian. When blood flow is compromised tissue starts dying due to lack of oxygen--it will turn purple then black signally tissue death. Your cat will not be using the foot if this is the cause of the color change.
Bruising can turn the skin darker colors as well though this is usually mottled and not pure black.
Some dermal irritation or diseases can cause pigment changes as well.
Your veterinarian will determine the problem and start appropriate treatment.

Abscesses are common in cats.  This could be related to infection.  This needs to be examined by a veterinarian to determine what is going on.  Tissue turns black when it becomes necrotic (tissue death).  Your veterinarian will make sure this is not an area of dead tissue that needs to be debrided (removed).