Lg G4 Phone died and will not restart

Jan 16, 2019
G4: phone suddenly died.Tried holding down the down volume and start/off buttons, nothing. Replaced battery and got nothing for several hours. Then tried holding down start/off buttons again and phone went to charging symbol. Allowed it to fully charge. Then tried holding down the start/off button and phone went to lg logo but would not go to screen and then died for good. I have tried once again the buttons and nothing so far. Can anyone help? Thank you.