I suspect that one of my kids has re-set something in my D3X, because it refuses to auto-focus. When I half–press the shutter, the lens goes forward then back and stops unfocused. Manually focused, I can take a shot but only when I hold the AF-L AE-L button at the same time, plus it takes a while, a couple of seconds. I tried two lenses, so I am sure it's something to do with the body.
The issue could be embarrassingly simple to correct (I hope it is); please help. Thanks!