My screen on my phone went black while I was on a game. I left it alone then held the power button till it turned off the turned it back on. Screen stayed black but the task and back buttons on the bottom lit up. Also tried taking out the battery and retrying same thing. BF said try letting the battery die off on its own and recharging to try again. Any ideas what could be the problem? The phones about a year old with no problems and it's a Samsung Galaxy s5 Neo I believe.