Why does my Lumia 535 keep restarting for no reason?

every now and then my phone will go through a phase of just restarting itself over and over and then it will work fine until I open the internet or an app that needs internet connection in fact any app I open the phone restarts. Phone isn't even a month old and I have installed the update that came and also the stop restart app neither have made an improvement.

Probably a stuck button somewhere. Have Nokia/MSFT replace it since it is only a month old. Good luck.