My Samsung Galaxy Note 4 died today. Just purchased at the end of May, and have had 0 problems before. Not dropped and no water damaged.
It was working just fine, almost fully charged, had just been using it and set it to the side. Picked it up and the power light was on, but it would not respond. Pulled and reset the battery, but no lights... nothing. Pulled and left out for a while... put it back in... tried charging for an hour... still no luck.
Decided to go to the AT&T store to see if it might possibly be the battery, and, barring that, hopefully get a replacement.
The young guy took it and looked it over. Did exactly what I did, pulling the battery and plugging it in. I was being polite, but, as a LONG-time PC tech myself, was resisting the urge to eye-roll. Then, as he replaced the battery, plugged it up, sat holding the buttons and, suddenly, the phone powered on, and popped up an orange message. He then restarted it, and it powered on up.
"What wizardry is this?", I exclaimed. I forgot to mention that I am a huge geek. :-!
He explained that pressing and holding Volume Down, Home and Power Button, for a good while, will sometimes fix these type of problems.
FANTASTIC!
No idea what caused the problem, but was just happy to have my phone back and working again.
Hope this helps anyone else that is Googling (or Binging - if anyone actually does that) for an answer.
Just press and keep holding those 3 buttons, and maybe you'll get lucky.
Good luck!
Robbie Wilkes