Welcome to Nikonians! Sorry to hear of your problem. Are you using a good AF target? Try cycling the AF/MF switch on both the lens and camera body back and fouth a few times. Have you tried cleaning the electrical contacts on both the lens and the camera body? Also moke sure the electrical contacts on the lens are all projection out the same distance. They are spring loaded and can get jammed in. Good Luck and Enjoy your Nikons!