You sometimes find yourself in a situation where your iPhone just won’t turn on. Pressing the power button causes literally nothing to happen; the iPhone just displays a black screen. You may think your iPhone is broken and that you're going to need to buy a new one. But there are a lot of things you can try to fix your iPhone before you decide it's completely dead. Try these tips to bring it back to its normal shape.

1. Turn It On/Restart It

If you iPhone won't turn on, check to make sure that it's not off. Hold down the Hold button at the top right corner on the edge of the phone for some few seconds. If the phone is off, it should turn on.

2. Charge the iPhone for a While

Try connecting your iPhone to a USB charger and connect it to a wall outlet for some few minutes, or better still, connect it through USB to your computer for at least 20 minutes , after doing that, try turning your iPhone ON as usual while your device is still connected to a reliable power source.

If your device battery is completely drained and very low then sometimes after maybe 10-20 minutes of being charged you will be able to press the power button and then see a screen display with an empty battery and icons showing a cable connected to a power source:

If you see that screen after the iPhone has been charging for a while, that means the device needs to charge longer before it will be usable again because the battery was completely dead. If you suspect your phone ran out of battery but this technique doesn't work, then there’s a possibility that your charger or cable is faulty. Try using another charger or cable and see it will charge.

3. Proximity Sensor Problem

Admit it! Your iPhone's screen turns on and off when you hold it close to your face to make a call due to the proximity sensor. This malfunction can cause the screen to be turned off even when the phone is on and not close to your face.

If this is the case, it can be solved through software, rather than repairing or replacing the phone. Just hold down the Home and Hold buttons as outlined above to restart the phone. When it restarts, the screen should be working. If it is do the following:
==> Tap the Settings app

==> Tap General

==> Tap Reset

==> Tap Reset All Settings. This erases all your preferences and settings on the iPhone, but won't delete your data.

==> Confirm the reset. Your proximity sensor problem should be resolved by now.

4. DFU Mode

In some situations, the issue might not be so much that your device won't work as that it won't boot very well. This often takes the form of the phone trying to start, getting to the silver Apple logo, and then restarting itself. This is common after jailbreaking.

If this is the problem you're facing, then try putting your phone into DFU mode and resetting it.

5. Force Reboot

Force reboot can be of great help! Hold down your device Power and Home button simultaneously until the Apple logo appears.

Hard reboot works if iOS has crashed or is frozen, which can sometimes manifest as an unresponsive iPhone with a black screen that appears dead because it isn’t responsive to anything. This is the easiest to determine and to resolve since it doesn’t even require waiting for the iPhone to charge before you can do it, and you’ll know nearly instantly if it works.

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