Why did my nikon d3000 go black?

I have a Nikon D3000, and every time I take a photo, it comes out black. (no, the lens cap isn't on.) I can see through the viewfinder, but the photo just comes out black. The battery is fully charged and there seems to be nothing else wrong with it.

Are you sure you you have a proper exposure?

put the camera on auto and take a picture in sunlight. If that doesn't work, something else is going wrong with your camera. See if you can restore factory default settings and try again. If that doesn't work, best would be for you to call nikon and ask about it.

You are clearly trying to use your DSLR like a point and shoot camera. If you want to use a DSLR, you need to learn about exposure. Your photos are black because they are underexposed. Either take a class it read a book called "understanding exposure" to learn how to use your DSLR correctly.

The doctor apparently has beaten me to it.

Set camera mode dial to Auto, ISO to Auto, focus to AF and EV to 0 (zero). Go outside under the sun and take a picture of a bright car or something. If the picture still comes out black your camera may have a broken sensor or a computer glitch. Contact the store you bought it from and ask where to have your camera be serviced.