Have you possibly dropped it recently or has it had any repairs? It sounds like it is coming on so you might want to put it on a charger and see if the following helps. Turn it on and try flipping the mute/vibrate switch to see if it vibrates. If it does that means it is on but there is a screen issue. Something else to try is plugging it into iTunes to see if your computer recognizes it, if so again it is on but the display has gone out. It sounds like the LCD has gone out or a connector has come loose from a drop. The only other idea that may help is to try turn it on, take a flashlight and shine at an angle and look to see if you see the apple logo or the normal home screen. If its already on then hit the home button while looking. If you do see the normal screen with a flashlight then it may be a logic board repair and that is not for your normal everyday person. It requires micro soldering. Let me know what you find, all of those steps should only take a few minutes. Hope this helps!