How to Force an iPhone to turn off
In this tutorial, we learn how to force an iPhone or iPod touch to turn off. First, hold the power button ( at the top of the device) and home button (one the bottom middle) at the same time and wait until the screen turns completely off. To turn back on, press the power button that is located at the top of the device. You will see an Apple logo pop up and it will stay on the screen for several seconds. After it's loaded, it will re-boot as normal and your regular home page will show up as it was before.