Stop shutting down

[Stop shutting Down]

Hi my son's phone keeps shutting down when trying to do anything. When loading up boxes pop up saying app is shutting down and it is just the standard apps. I have deleted every game he has and tried to clear the cache but while doing all this it will shut down or sometime freeze I have to take battery out then. What else is there to do and how to clean the virus out? It is a Samsung galaxy s5 I believe. Help please really do not want to buy another phone at moment!

 

[Dannydet]

Just do a factory reset and make sure you know the correct Gmail account and password