Nikon D80 Autofocus problem

probably you have problem with the focus motor, i ever have same problem and need to replaced the focus motor.

That lens will work with the D3100, except for the autofocusing. In order to autofocus with the D3100, you need AF-S lenses, such as the AF-S VR Zoom-NIKKOR 70-300mm f/4.5-5.6G IF-ED or the
AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR.

set the autofocus swith in the camera beside the lens to AF, and in the lens switch to AF

I fix these all the time for this problem, The focus motor is bad, Tony

Hi,
Sorry to hear about your lens. If you are able to autofocus and take pictures with any other lens, then it means that your problem lies with the kit lens. If you can take picture in manual mode, but not in autofocus mode, then the AF motor in the lens in not functioning. I had the same thing happen to my 50mm 1.4 lens.
Depending on your location, there are Nikon repair centers in Melville, NY and Torrance, CA.
Hope this helps,
Andrew

Check to make sure the manual focus/auto focus switch on the lens is set to A. Make sure the lens is completely mounted to the camera and locks securely. If this does not help, or if the lens was dropped, then you should consider buying a new lens. the cost of fixing the old lens may be at least half of the cost of buying a new one.

problem in lens censer try to set the censer or replace it

Seems as if you're snapping the shutter before the lens has focused. Have you tried manual focus or single-server auto focus?

Please check your focus settings in the camera menu. Play around with the focus point from Single to 11 points. Also, try Auto mode as a quick way to test if the focus is working

You might like to check if the A/M slider switch on the lens by the Nikon label is set to A.
It sometimes gets moved accidently.
Set to M the lens will not autofocus.