My Galaxy S3 turned itself off this evening and now won't function at all. In the past I had issues with it turning itself off and getting into a reboot loop, but eventually the issues would go away. But not this time. When the phone boots, the Samsung Galaxy S3 screen comes on, and then the phone turns off a second or two later. It is then unresponsive until I take the battery out and put it back in, or wait a few minutes. When I take the battery out and put it back it in, the phone vibrates, begins to start up, and then dies. I tried my spare battery and the same thing happens. Leaving it plugged into the charger doesn't make a difference. I tried to do a factory reset but the phone dies before anything happens. Anything I can do to fix this, or is my phone toast?