1. Charge the PhoneThis is something you would naturally try if your phone doesn’t turn on, especially if you were using it for a long time that the battery was drained out. You can insert it into a plug point and leave it for 15-30 minutes. Then check if you can turn on.
A better way is to plug the phone into one of the USB slots in your computer. This way the phone turns on manually after it is sufficiently charged. Even if there is a problem with the power button of your iPhone, turning it on this way will fix it.
2. Restart the PhoneTry resetting your phone by long pressing the Power button (the button on the top/side of the iPhone). Slide to turn it off. When the phone is turned off, long press the Power button once again to start it. Make sure that you do this after the phone has been sufficiently charged. If normal restart isn’t helping, then:
- Press and hold the Home button and the Power button simultaneously for a few seconds.
- When the red slider appears or the screen dims out, keep pressing the two buttons until the Apple logo is seen.
3. Restore to Factory SettingsIf restarting your phone isn’t working, then try resetting it. You will lose the data that you have stored. It will put your phone back to default mode. It won't be a problem if you have the proper habit of syncing the data in your iPhone to iCloud. To Restore simply follow the steps mentioned below:
- Plug the iPhone's USB cable into the Lightning/Dock Connector port, but not into your computer.
- Long press the Home button.
- While keeping the Home button pressed, plug the other end of the USB cable into your computer.
- This opens iTunes. Put your iPhone into the recovery mode, and then you can completely restore the iPhone.
4. Put iPhone in DFU ModeAt times, your iPhone will not turn on because it doesn’t boot up. This happens when you jailbreak or try to install and iOS update without sufficient battery in your phone. In such cases, putting the phone in DFU mode will work as the fix:
- Plug the phone to your computer.
- Long press the Power button and release it after 3 seconds.
- Long press the Power button and Home button together and release after 10 seconds.
- Long press the Power button for about 5 seconds and then release it.
- If the screen doesn’t show any changes and appears black, you are in DFU mode. Follow the iTunes instructions onscreen.
Final WordsThe ultimate solution in cases all other ways fail is to take your iPhone to the Apple Customer Service and get it repaired. If your phone is new and still in the warranty period, you will get it replaced if the issue is due to the hardware or get it rectified otherwise.
If your phone is past the warranty period, fixing equipment damages might prove to be a costly affair. Either way, get the help of an expert or contact the Apple Team online rather than breaking open the phone on your own and creating a mess.