Was browsing Youtube. The phone suddenly went black or dark blue. I managed to turn the phone off using only by pressing Power Button and Home button simultaneously. After that, the phone resisted to turn back on, but after some rigorous tries, it showed some life signs (1. An apple logo on a white screen appeared, but nothing after that happened. It was just stuck in that position. 2.The apple logo appeared and then the same black (dark blue) screen that was in the beginning. After that no matter how I tried I was unsuccessful at repeating and forcing the phone to display the apple logo. Phone nonresponsive , doesn't vibrate, doesn't display any sound. Tried charging it. Tried connecting it to the computer (doesn't even recognize that I connected it). Everything was normal and nothing unusual was happening before this event. Could you please guide me towards what could be wrong? I have a spare battery that I'm willing to try changing, but if it's the logic board, I think I'll just give it to a specialist.