My son's kindle fire HD 8 was working fine last night. He turned it on this morning and it is now stuck on the fire logo screen. I have tried holding down the power button multiple times for all the seconds recommend. I have tried the power and volume down button and restarting it from there. I have tried leaving it plugged in. I am now at a loss of what to do. Help please. We just got Wi-Fi yesterday and now he can't use it.