Be sure to do the iTunes trick because this will tell you whether or not its just the screen. Otherwise, I would open up your phone and check to see if maybe one of the connectors is unplugged or damaged. I just read you replaced the battery and now its having a hard time charging. Do you have a voltmeter? I would use it to check your charger, then check the battery, and then check the board itself. Open up the phone, you can take the screen off for this if you want, I do because less risk of damaging it. Now disconnect the battery. Plug in your phone to a power source. Take the voltmeter and touch the connectors to the battery terminal. Youll have to move them around alittle until you see voltage, if you do. This can help determine if its the board, battery or the charger.