1.
Put in freezer for 20-30mins make sure battery is in different bag (take battery out of phone ) this is not gimmick works on all Samsung's that work fine when running but have the won't turn on and charge problem
2.
Put on charge for a few minutes then start phone
3.
Install wake lock from google play for running probs and engage partial wake lock in app
This will stop phone from shutting down and your phone will run like new even with all the crappy updates
I did this as phone kept shutting down and restarting
New battery is a must for note 4 older than 2 years
And last but not least for God sake don't let your note 4 run out of charge and turn off they don't like it lol
If this does happen just do step 1 again if having problems starting phone
# note 4 won't charge
# note 4 just turns off
# note 4 shuts down
# note 4 crashing
# note 4 won't charge
# note 4 won't turn on