The simple things to check: 1. The exposure mode. If it was inadvertantly changed to Manual (M) with a fast shutter speed and or with the aperture stopped down that could easily be the cause of your problem. You might also want to try different exposure modes and see if there is a problem with the mode dial. 2. Exposure Compensation. Though less likely, check the Exposure Compensation and make sure it is set to zero. 3. Is the viewfinder dark? If yes, Make sure the lens is fully mounted and locked in the mount. If it is still dark, the problem could be the stop down mechinism on the camera or a sticking diaphragm in the lens. 4. Is the shutter opening? Place the camera in Manual exposure mode. Set a slow shutter speed like 1/2 sec. Remove the lens. Turn the camera on and release the shutter while looking into the light box. The mirror should go up and the shutter should open for a 1/2 sec. then close. If everything is working normally, and the images are still black, it is time to send the camera in to Nikon Service or a Nikon Authorized Repair Station. Good Luck and Enjoy your Nikons!