I recently got a Galaxy S3 from Verizon because my DINC was stuck in a continuous reboot loop for hours a day.
Well now for two days my S3 has been doing it. It turns on, gets to the security screen and is unresponsive, moments later it goes dark (maybe off) and then like a minute later will light up to the security screen and still be unresponsive, it just keeps doing it over and over. I've pulled battery, left out for 2 hours, put battery in and charged it OFF, turn it on and same thing.................. I'm getting tired off these dumbphones.