If the PS4 still won't turn on, try using a different power cable or outlet to see if it helps. Boot your PS4 in safe mode to fix software problems like incomplete updates or corrupt files.

You can turn a PS4 off or on using either the power button located on the console or a paired or connected controller. Here's how to do it.

PS4 ‘won’t connect to PSN or turn on after Rest Mode’ following System Update 2.0, users report By David Scammell Last Updated October 28, 2014 ...