1. If you immediately notice that some buttons or levers are dirt or wet, turn OFF the camera and use a soft, dry cloth to wipe the buttons and controls down.
2. Maybe a button has jammed and is blocking the other buttons: go over all the camera controls and press them a few times.
3. A quick solution might be to turn the camera OFF and back ON to correct a momentary glitch. As a next step, you might even remove and reinsert the battery in the camera.
4. Finally, try to reset the camera to the factory settings (initialization). Consult your product manual if you're unsure about the reset procedure.