Sony

Do you have a Sony Xperia Z1, and the screen appears to be dead / off, but the phone is actually on in the background (to verify if it is on, try calling it from another phone for example). The following trick will probably fix the problem: Hold down the Volume Up button and the Power button for about 10 seconds. You should feel 3 vibrations.  This will turn your phone off. Wait a couple of seconds, 20 or so. Hold