I recently bought a Nikon D3100. But I have a problem now: I can't change shutter speed, ISO, or aperture in any mode. I am stuck at 1/100 and when I try to wheel it shows me 1/80 for a second and then switches back to 1/100. Same for other settings. When I switch to automatic the settings change.
Same in the image view: I switch one forward it switches back.
How can i fix it? I have tried to reset settings, but that didn't work.