On my Nikon D7000, the Exposure Mode Dial suddenly changed its alignment. When I select P, the camera chooses A. The setting indicated on the selector dial does not match the setting as shown in the screen. What shall I do?
If the offset is constant, you may need to take the dial off and put it back on again. It may just pull off, or you may have to prise/peal off a cap and undo a screw.
By a constant offset I mean that a on dial with 4 positions A-D, selecting A would give mode B, B woudl give C... D gives A (or similar)
Chances are good you'll have to send it in for repair, but you can try using a bulb blower to blast the knob, to make sure that it isn't just some loose random dirt up under the dial keeping the contacts from making contact. You can also press down the dial while making a full turn to see if you can knock the dirt out.
To add to Chris's answer.
If it looks like the setting is always the same amount off like described by Chris H it's likely that the knob got shifted on the actual switch inside. Imagine taking a clock and rotating all the numbers a couple places. When the clock is at position 12 it shows 2, when at position 1 it shows 3 and so on.
Send it in for repairs to Nikon
Less Risky Option - insert try at your own risk blurb
If you can take the knob off you should be able to just shift it back into the correct position. You might be able to pull it off or pop it off with a screw driver or something.
If you don't want to take it off you could see if it's able to be shifted back into position, as it must have been shifted out of position without being removed, by trying to turn it without actually changing any settings. What I mean is try maybe pulling up on the knob while rotating it. This could disconnect it from the internal switch and you might be able to rotate it back into place. If the knob can only be turned so far in one direction try to over rotate it back into position.
Now these are all probably bad ideas but if you're desperate you can give those a shot but try at your own risk.