Hi I have a rooted galaxy s3 from sprint, never flashed any new rom just kept the stock one. My phone lately started rebooting itself at random until one day while I played subway surfers, it went black. When I try to turn it on, it lights up, the first "samsung" screen flashes quickly, then it stays stuck on the "samsung galaxy sIII" screen forever. The first time I went into download mode it flashed a quick message and went black. Now I cannot go into download mode at all, it just vibrates when I do it and that's it. (I press home button first, then volume down, then power button). when I connect it to the computer with Odin on, nothing happens. I can't return it to Sprint because I'm out of contract now. I bought a jig on ebay but I'm still wondering what the hell happened, and if the jig is the only solution? Any thoughts? thank you. P.S. When I plug it into the wall or pc to charge, it vibrates but then there's no battery charging animation, so I can't tell if it's charging or not.