How to get my lens to zoom?

Ok, so I have a Nikon D70 and my 70-300mm lens will not zoom in, it will auto-focus, but it stays at the same zoom level no matter what. When you turn the dial to zoom the lens doesn't extend and it doesn't zoom in at all. What can I do to fix this?

Are you sure you are tuning the ring for zoom and not trying to turn the focus ring? Is there a little lock switch somewhere on the lens that stops the lens from extending out? Many zoom lenses have such a switch to prevent the lens from extending out when carrying the camera with the lens pointed down. If you are indeed turing the zoom ring, and the zoom is not locked, and nothing happens, it sounds to me like there's nothing YOU can do to fix it. Nikon repair would be where it probably will need to go.