My phone keeps restarting on it's own

Hey! I have a Samsung Galaxy LTE Prevail and I had it for a while now and it keeps restarting on it's own. Sometimes it will work then a few seconds later it restarts and it does it again. I took the battery out and tried to see if it will work. I turned my phone off and waited for a few minutes and tried it and still did it and I even put it in the charger to see if that is the problem. I seriously have no clue why it is doing this. If someone could help me, that would be great.