I had the problem with my phone going dark and/or completely black and sometimes unresponsive. If you can still see your icons, even just a little bit, then go to your Settings icon and select, then scroll down to General and select, then scroll down to Reset and select. You will get several options. I selected the "Reset All Setting" and this changes the settings, but leaves all the data and content on the phone. Apparently my phone has been going dark for quite some time and now it is bright and clear. I will just have to go back through my phone to see if there are any settings I need to change as it has been so long that I don't know if I would remember what I had them set to. So far the Locations; Wi-Fi; Bluetooth; etc. settings need to be reset.