Well, although it’s rear behavior, Android device sometimes jam, for numerous reasons. Only way to unjam them is to reset device. But how if your screen does not respond? OK, you can remove battery, but what if you have device where removing battery is not an option?
If you just want to reset android device in case your screen is not responding, press power button for 10 seconds. Your device will be restarted. In some cases time needed for reset/shutdown is longer or shorter then 10 seconds, depend of manufacturer.
Now, you want to revert device to factory default. First be sure you turned off your device. Then, press in the same time Volume Up & Down and Power button. You will need arround 10 – 15 seconds for this action. When screen popups navigate with Volume Down to factory reset option. Select option with power button.
I hope this tutorial was informative to you and O’m looking forward to your feedback.