I have a Nikon d3100 with the nikor 18x55 lens. Whenever I attach the lens and turn the camera on it's simply saying "lens not attached". The only time it will take a picture is in manual mode and it's a self timed picture...? Any suggestions to make my camera work? As I said, I'm just learning everything about it.
Try cleaning the contacts and reattaching the lens. If that doesn't work, try a different lens to determine if the lens or the body is the cause of the problem. Send whichever part is broken to Nikon for repair.