Try these steps: 1) If HTC One (M8) does not respond when you touch the screen or press the buttons, you can still restart it. Press and hold the POWER and VOLUME UP buttons for at least 10 seconds. HTC One (M8) then restarts. (some articles say use the volume down button instead)
If that does not work next try: 2) This video shows how to do a complete reset, but you would lose all your content - returning the phone to factory new.
i trıed everythıng even reboot nothing ıs working. ı even got to my settıngs and force stopped home sense. ıts not working. the phone is still under waranty i bought it in april. but im on the other side of the Globe now.