The unexpected happened this afternoon. My Nikon D200 camera suddenly stopped working properly. It no longer auto-focuses. I had switched it to manual focus while experimenting trying to taking pictures of falling rain drops during a thunderstorm. When I switched it back to autofocus it no longer worked.
At first I suspected it was a problem with my lens, but I tried a different lens and get the same behavior - the autofocus motor whirs and whirs but the lens doesn't move.
Looks like I'll have to send it in for repair. Good thing I kept my older Nikon D50 as a backup. I wouldn't want to miss the chance at some prime fall weather photos.