Nikon 3100 pictures are coming out black?

I have previously asked this question before but I did not get the answer that I was looking for.
A couple of weeks ago I have started to face difficulties with my camera. When I went to go take a picture the picture came out black ( yes I have taken off the cap ). And my live view is also black. I have never dropped the camera before so i would love to know what is wrong with my camera. Thank you.

Added (1). Yes i have looked through the view finder it is not black what so ever.
but the pictures are still coming out black and that is what i don't understand.

Can you see through the viewfinder? (If you can't, the mirror is locked, This is either you pressing the wrong button, a dud battery, or a symptom of something Nikon will have to know about).

If you're shooting manually and not paying attention to your meter display, your pictures could be under-exposed.

I'm assuming that you've charged the battery (take it out, stick it in the charger, and plug the charger into the mains) because it takes a special kind of idiot to try to charge a DSLR through USB.

Is your Live View turned on? (I've always seen Live View as a great way to drain the batteries while holding your camera in the worst possible way, but some people like it).

Have you read the trouble-shooting section of your manual?

Have you discussed the matter with the person who sold you the camera?

If your camera is faulty, only Nikon can diagnose and fix the problem.

If you're doing something wrong, learn how to do it right.

If the settings on your camera aren't set properly, this could be… And is most likely to be the cause of your problem. To get a balanced exposure you have to understand how to compensate for different lighting conditions by using the settings on your camera… Iso setting, shutter speed and the aperture control. A decent photo guide will help you to see what is involved and will illustrate with pictures what happens when you don't get it quite right.

It isn't as technical or difficult as it sounds, pop down to your library and bury your head in a book for an hour or two.

Actually I'd say it's operator error. What's your f/stop set to? What's your shutter speed set to? What's your lighting conditions when you get "black"? All of that matters so check those things first before assuming your camera has failed.

And why are you using that stupid live view anyway? Have you bothered to look through the view finder? Is that black?

If you put your camera on auto, take it off live view, and go outside on a bright sunny day, and take a photo of a distant object - does the camera take a correct photo?

If it does, then you are doing something wrong. If it doesn't, there's something wrong with the camera.