Accidently erased OS

[Lidwien]

It looks like there is something with your power button.
If you have a slim case, it could be worth to take of the case and switch the button of the power with the button of the camera.

@AnotherElk in thread "Slim Case - Reboots and Button-Issues"

The buttons are embedded in flexible strips. These strips are fixated to the case on both sides of each button. It isn’t so obvious at first, but you can carefully pull the strips (including the buttons) off those fixating points. And if you’ve done that, you can carefully fixate the strip with the camera button to the power button’s place (if it won’t snap in place easily, use a fingernail or some not too sharp tip of some kind to gently push it in place) and the strip with the power button in the same way to the camera button’s place … and voilà