It's of no consolation, but buy your new phone from Best Buy and get their protection plan. I've gotten no less than 5 Galaxy Prevails and Rushes from them when I have problems.
Also, wiggle the cable connections and check the battery. Some charging cables get loose after a while and scare you, but you get them going. One time the "springs" that touch the battery terminals were bent in too far and I bent them back out and it started working again.