I have just resurrected my D100 from the attic after many years of good service. Unfortunately I cannot find the instruction manual. I have tried to use this camera with an older 35-105 3.5/4.5 D lens. but cannot achieve focus, should they be compatible in any, or all modes? I feel a bit embarrassed at having to ask this question having been a Nikonian for many years.
The D100 has an AF motor built into the camera body that will drive the screwdriver type AF mechanism in your 35-105mm lens. Make sure the AF switch on the front of your D100 is set to C or S. If the AF doesn't work, try cleaning the electrical contacts on both the camera body and lens. Good Luck and Enjoy your Nikons!