So, disaster has struck: your iPhone won't turn on! You've checked that the battery isn't depleted, you've tried all sorts of button combinations, and it still won't work. But before you give up and call Apple for help, there are things you can do; steps you can take. While it's true that hardware fails, it's more likely to be some kind of software glitch for which you'll need to find a workaround.
So, follow along and we'll try to get you back up and functional in no time!
1. Plug in
Yes, I know, you're sure it's not the battery and you're sure you're charged up, but let's make double-triple sure. Maybe something caused your battery to drain faster than you expected, or maybe your charger or cable wasn't working, so it's worth checking.
Grab your Lightning connector (or USB-C cable, for an iPad Air or iPad Pro) — preferably a different one than you used before — plug into an outlet or USB port, and leave it for at least an hour. If that works — if it boots up and starts working — great. If not, keep going!
2. Hard reset
If your iPhone or iPad won't turn on, one of the first and easiest things to try is a hard reset. Whether it's really not turning on or it's just frozen on a black screen, or it really hasn't booted, a reset can help. Yes, it's the old "reboot Windows" solution, and it's silly, but it works. Sometimes bad bits get stuck and need to be flushed out.
Of course, how to reset your iPhone or iPad depends on what model you have, so you'll need to follow those specific instructions.
3. Restore
After trying the easy fixes, it's time to try the harder ones. In this case, restoring your iPhone or iPad in iTunes. iTunes is a safer bet than iCloud because it actually offloads, re-installs, and reloads your data rather than doing everything in-place and on your device. That can sometimes shake loose bad bits that even a hard reset or iCloud restore can't.
Your iPhone or iPad will have to be functional to restore — even if it's not booting directly — but plugging into iTunes should answer that question almost immediately.
4. Contact Apple
Real talk: Sometimes a problem is really a problem. Electronics can fail, and they can fail at any time. If you have AppleCare+, make a Genius Bar appointment at the Apple Store or call Apple at 1-800-MY-APPLE to set up a mail-in repair. If you don't have AppleCare, you may have to pay for the visit or call, but it's less of a waste than having a dead iPhone or iPad.
Your fixes?
If you had an iPhone, iPod touch, or iPad that won't start up, and one of the above fixes worked for you, let me know! If something else worked, let me know that as well!
