Ahem, hi, my names Ama. I got a used nikon D3100 on christmas last year from my grandpa. I still consider myself a newbie in photography (same with this forum, never used one in my life). However recently (like 2 weeks recently) I was using my D3100 and something strange happened. The camera completely froze! It started with not wanting to focus, then it didn't want to change any of the settings like shutter speed, f stop etc (I was using the manual setting btw, lens in auto focus) and the strangest of all is that even turning the camera off it didn't turn off! I had to take the battery out in order to shut it all down! Once I inserted the battery back in it all went back to functioning as it should. It's happened twice now and I don't know nor understand what's going on with my baby. Please, does anyone know what could be happening with my camera? Any info I can get my hands on will be helpful.
Try a new memory card. Pick one from Nikon's approved list for your camera. If it still happens with the new card, then it might require service from Nikon. Here are some links describing similar issues with the 3100. Both found by searching google for thw words - D3100 freezing up - if you want to do any additional research.
http://www.dpreview.com/forums/thread/2930347
http://www.fredmiranda.com/forum/topic/1058606
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