The not responding iPhone is not a new problem, and it continues for iOS 9.3/9/8. After updating to new iOS, many iPhone users report that iPhone can't switch off. When try to turn off iPhone by pressing the Power button, the Apple logo will appear telling that iPhone is in recovery mode or the iPhone just turns off unexpectedly.
Indeed, this is quite frustrating. In this post, we've summarized some possible fixes for you to use when iPhone not responding to anything and can't turn on or off normally.
Here are 2 solutions for you to deal with the iPhone not responding issue and it works for the latest iPhone SE/6s/6/6 Plus and iPhone 5s/5c/5/4S/4 alike.
If your touch-screen is unresponsive or you can't quit a troublesome app, then reset your iPhone. Press and hold both the "Sleep/Wake" button and "Home" button at the same time. Don't release either button until you see the Apple logo appear on your screen about 10 seconds later, indicating a restart. The reset will likely fix whatever prevented a shut down in the first place.
If the screen remains black, verify that the device has enough charge to turn on. Let it charge for at least twenty minutes, then see if it starts normally.
Tenorshare ReiBoot or Tenorshare ReiBoot Mac is a small but powerful freeware to easily get iPhone, iPad and iPod out of or into recovery mode, DFU mode, reboot loop, etc. The working mechanism is quite simple: it forces iOS devices to reboot and therefore fixes issues resulting in the not responding iPhone. That's an extremely considerate move for those whose iPhone screen not responding to touch.
You can now give yourself a break as your iPhone is running smoothly again. Hell, can't find Camera Roll in iOS 8? Read this post to find lost photos in iOS 8.