What's wrong with my camera and how much will it cost to fix?

So in may 2012 i bought this nikon camera at best buy i didn't buy a warranty because it was too expensive all together. Anyways about a year later i was using it and it was working fine but suddenly it wouldn't turn on i assumed it was the batteries but when i got new ones it still didn't turn on then i pressed the play button to see pictures and it turned on but i wasn't able to take pictures or turn it on or off with the on button. It still looks new i always keep it in its protective case so it couldn't have gotten damaged if it accidentally knocked into something. So if someone has some ideas of what could be wrong and how much it will cost if it can be fix i would appreciate it, thanks.

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