My phone just randomly turned black so I figured it was over heated, so i just let it chill for a little and plugged it in. It vibrated when I plugged it in, but still didn't turn on. I looked on here and realized that people were saying they had to replace the screen. I found a very helpful video on youtube that first says to press the home and lock button down at the same time which is what I had already tried. If that doesn't work then hold down the lock button for 3 seconds, then hold the home button down with it. That worked for me. No need to replace my screen!!!