Why won't my Nikon D90 DSLR auto-focus or take pictures?

I believe that means you are using one of the auto or semi-auto settings and the camera is unable to find an aperture which will give you a properly exposed picture. I would recommend that you learn how to use your camera on full manual mode like a photographer and these things will not happen. There are several good books out there that will teach you how to use your fine camera like a photographer does, instead of like a really expensive point and shoot.

It seems a shame to spend over a year yelling at everyone in sight and to not spread the word to other people when I finally found it. The problem is probably mine. There is a connection between the lens and the camera body that causes them to coordinate with each other. Mine would do the same thing take a few--everything great. Then it wouldn't take some with an f--- error. I would work if I picked up the camera and tightened or fiddled with the lens for a few seconds. The store tried to tell me it wasn't all that bad as a problem. I told him trying to catch children at just the right spot and have the stupid camera not work was not what I wanted. They said send it to Nikon. Nikon said give it back to the store. The store said give it to their repair man etc. The repair man said they do have a few cameras that have this problem. After stomping my foot for almost 1 year, they gave me a new camera (the store.) And while it doesn't have that problem, it is not a crisp as my older Nikon. I am switching to Canon.