What happened to my Samsung S4

[Android Central Question]

Just done a update on a Samsung S4 and now everything Google has been wiped and the phone has gone of and won't come on any ideas thanks

 

[B. Diddy]

Welcome to Android Central! Was it an official system update pushed over-the-air? That would be somewhat unusual, given how old that phone was. Or did you manually download the update from some website and install it yourself?

How do you know everything Google has been wiped if the phone won't even turn on?