My galaxy s3 won't stay charge or turn on.

My galaxy s3 last week starting to only charge with a certain charger. And worked fine now  it shut off and now doesn't stay charged long and its a brand new battery..

And now it doesn't turn on 99% of the time. When I push the power button it takes me to the Samsung logo then goes blank. Once in a while maybe twice a day I can get it to go to the whole process where it completely works but 5-10 later it will shut off and won't turn back on for hours.

No it was not dropped in water or dropped on the floor. It was in my pocket when it started acting up. I have even tried to reboot it and it won't finish going through the process. If I could just turn it on to save my pictures and data that all I need. But my phone back would be nice too.

Thanks