I have a Nikon D5100 and all the pictures started showing up black, any ideas?

I have a Nikon D5100 with a Tamron lens, and my aunt was taking photos in quick succession just for fun. When we looked at them all, they were just black, no color or anything. It was taking photos very normally up to that point, so this came very out of the blue. Does anyone have any idea about what might be broken?

Added (1). I've tried every setting and nothing has worked.

Black = gross under exposure

Are you using your cameras light meter?

Try that. You will be amazed at the results.