Nikon D40 Turns off when I take a picture

Just got a new Nikon D40 and am wondering why everytime I try to take a picture it turns off, its getting really annoying! It will also say "sorry not enough light" I know that is something pretty much a 5 year old could explain, but even when I try to get to extra light, it still doesn't take the picture.

Are you still in contact with the seller?

The D40 can't be new. It's ancient.

Set camera to P mode, EV to 0, white balance auto, ISO to auto and AF on. Go out and take a shot of a brightly colored car parked under the sun. If that doesn't come out right, change the memory card to one that is verified to work (preferably new and freshly formatted). If that doesn't still come out right, recharge the battery overnight then try again in the morning. If nothing seems to work, then you can now conclude that you have been duped. I'm sorry to tell you but you should have tested the camera thoroughly first before handing over your precious cash. It's not always about getting the cheapest. It's about getting your money's worth and making sure it works.

You got a new 6 year old camera? Where? Sounds like somebody sold you their headache. Need more info.