Realizing your iPhone won't turn on can be a traumatic moment. Before you despair that your expensive gadget won't come to life, perform a few simple troubleshooting steps to root out the problem. Sometimes users overlook easy explanations, such as a lack of power, a faulty case or an improper method for turning on the phone. Resetting or restoring the phone can solve other, more complicated problems.
Charge your iPhone. While this device has a long battery life, it may sometimes drain faster than you expect, depending on whether you're using 3G, Wi-Fi or the camera. Plug your iPhone into your wall charger or your computer and let it sit for at least 10 minutes to see if it charges. If you don't hear a sound when you plug it in or if the screen remains black, there may be a problem with the phone beyond a low charge. Plugging it into your computer may cause it to be recognized by iTunes. If your phone is truly dead, nothing will happen.
Cases and Proper Turn On
If your case slides out of place or you accidentally put your finger in the wrong spot, your screen may go dark because the Sleep/Wake button on the top of the phone has been pressed. Click the Sleep/Wake button twice. If this doesn't work, try to turn on the device by pressing the Sleep/Wake button until the power bar appears, a process that takes between 5 and 15 seconds.
Reset and Update
If the power bar doesn't appear when you press the Sleep/Wake button, reset your phone, which is similar to rebooting a computer. Press the Sleep/Wake button and the Home button at the same time until the Apple logo appears, between 5 and 15 seconds. Repeat if necessary. If this doesn't work, plug your iPhone into your computer. Make sure iTunes is updated, as well as your iOS software and all of your apps.
The final solution to any iPhone problem is a restore. This returns the iPhone to factory settings, which means it erases everything on the phone and reinstalls the iOS software. If this doesn't fix your problem, you have permanent physical damage that requires professional repair. To restore, plug your iPhone into your computer and click your iPhone's name in the left column of iTunes. Click the "Restore" button in the center of the screen and follow the prompts in the dialog box to complete the process. You can reload your media when you are finished. Jailbreaking is a common cause of a sudden black screen and restore is often the only way to repair the damage.