No matter what you do, you can't get your cell phone to turn on.
Before delving into the guts of your phone, .... read on.
If .... the problem most likely lies in the logic board.
After turning on the device, there is a blank white screen.
Try powering down the device and then removing the battery. Wait 15 seconds, then place the battery back in the phone.
The phone may have a bad display, and may need to be taken apart. Link to "Repair Guide".
The device may be water damaged. The device may have to be taken apart.
==Frozen or Jammed Keys==
Sometimes the buttons get jammed when they are pressed too hard, or the phone may have been dropped. The device may need to be taken apart to repair the jam. Link to "Repair Guide".