'Why won't my iPhone turn on？': 3 ways to troubleshoot an iPhone that won't restart

If your iPhone won't turn on, most of the time a simple restart will get it back up and running. If you can't restart your iPhone, then make sure it's charged. You might need to replace the Lightning cable and make sure the power source is working properly.If all else fails, plug it into a computer and see if iTunes recognizes the phone. If it does, try to back it up before you get it serviced or repaired.Visit Business Insider's homepage for more stories. It can be terrifying if your iPhone won't turn on — especially if you're not a tech guru. It might seem like there could be a million things wrong, and who knows where to start？ Is it even fixable？ It's never good when this sort of thing happens, but the good news is that most of the time, it's not hard to narrow down the problem and get your phone working again. In general, you can narrow down the problem to one of three key issues:A software glitch is preventing the screen from coming on. The phone is probably already on, but sleeping, and you need to restart it to wake it back up.The phone is dead, and it won't charge because there's something wrong with the cable or the way it's trying to charge.There's a serious hardware problem with the phone. Check to see if you can restart the phoneYou probably know that your phone is turned on all the time, even when the screen is off, unless you deliberately shut it down via the Settings app. When the screen is dark, the phone is powered on — albeit “sleeping” — and a software glitch in an app could be preventing the phone from waking when you press the Power button, tap the screen, raise it to your face, or however you try to wake it up. The simplest remedy is to restart the phone. How you do this varies depending upon which model you own, so read our article, “How to restart and force-restart any iPhone model” for the exact procedure for your phone. If your phone restarts successfully, your problem is probably solved. This problem can happen occasionally without suggesting a serious underlying issue. But if your phone won't turn on frequently enough that it's a nuisance, that suggests you have a misbehaving app or some corrupted data on your phone. In that case, you might need to reset your phone to its factory settings and then manually reinstall apps from the App Store to see which one is bugged. Try charging your phoneIf it doesn't appear that you can restart your phone, then it's likely that your phone is already powered off, and the battery might be dead. Here's what you should do: Attempt to charge your phone — connect your phone however you usually charge it and let it charge for an hour or two. If the phone still won't come on, there might be something wrong with the way it's charging. Check the phone's Lightning port to make sure it isn't filled with lint or debris, and inspect your Lightning cable for kinks, breaks, or frays. If necessary, swap the cable for another.Charge the iPhone again. Be sure to plug the phone directly into an AC adapter rather than a computer's USB port, to make sure the USB port isn't an issue. And make sure the outlet is working properly!It's entirely possible that the Lightning port or your laptop's USB port has failed, and since it wasn't charging, you couldn't turn it on. If so, this should solve your problem. Read “'Why won't my iPhone charge？': How to diagnose and fix common iPhone charging problems” for more advice on this problem. Troubleshoot a hardware problemIf the phone won't respond to a hard reset and doesn't appear to be charging, the number of potential issues has narrowed, probably signaling that it's a hardware issue. This isn't good news, because it suggests you might have a serious issue. Some of the most likely issues include:Water damage. You might have gotten your phone wet and it has caused some components to fail.Drop damage. If you've dropped the phone, it might have damaged the screen (most likely) or internal components (less likely), preventing it from working. Component failure. As reliable as iPhones are, it's always possible that one can fail due to a manufacturing defect. It's rare, but it can happen. To see if your phone has any life in it at all, try this:1. Connect your ailing iPhone to a Lightning cable and plug it into a computer.2. Start iTunes on the computer.3. Check to see if iTunes recognizes the phone. You should see the icon for the phone appear in the top left of the iTunes window. If so, you're in luck — the phone is actually powered on, and you can probably back it up. 4. If you see the iPhone icon appear, click it and then click the “Summary” tab on the left of the screen. In the Backups section, click “Back Up Now” to try to ensure you have a good backup of your phone's apps and data. You can later use this backup to restore your phone after it's serviced or replaced.5. If you don't see the iPhone icon in iTunes, your phone is beyond your ability to even back up — sorry.6. Contact Apple to have your phone serviced or replaced.Related coverage from How To Do Everything: Tech:'Why won't my iPhone charge？': How to diagnose and fix common iPhone charging problemsHow to restore your iPhone from a backup after taking the 'nuclear option' of a factory resetHow to backup an iPhone to iCloud, your computer, or an external hard driveHow to free up space on an iPhone that's running out of storage