Camera won't let my take pictures when its dark?

I have a Nikon D3100 (i'm new at this) and it won't let me take a picture when it is even remotely dark (i'm not talking about trying to take a pic in a completely dark room) even when its a little dark it won't let me take a pic it says its "to dark"! I have tried in every setting but it still can't please help!

Put it in Aperture Priority mode, put the f-stop to f/3.5 (assuming you have the 18-55mm kit lens), set the ISO for 1600, and see what shutter speed it reads. If it is dropping below 1/30sec, raise the ISO.

Your camera is struggling to focus thus deactiving the shutter.

Two sollutions.
1. Manual focus
2.Se a small flashlight in your left hand to shine sone extra light so your camera can focus properly

I presume you have it in auto focus. You can't take a shot until it focuses on a subject (the whole point of auto-focus!).So you'll have to put it in manual focus and do it yourself. Make sure you have a low enough shutter speed coupled with a high enough ISO.

Also, be sure that you have the auto-focus assist light on.

If you are in AF-C mode, the shutter will release whether you are locked in focus or not.

If you set exposure in "M" mode, it should shoot regardless of the light level.

Well, it sounds like you need to learn how to use your camera properly… In manual mode. Stop letting the camera tell you what you can and can't do. Sign up for a class and learn how to control your camera in manual mode.