If you've previously tried the basic drills, including a forced restart, to bring your iPhone back to normal functionality but haven't had any luck, you may troubleshoot the software using iTunes. You should do it first if you haven't already. Simply press and hold the Power and Home buttons together for 10 to 20 seconds until the iPhone SE restarts. If it doesn't work, use iTunes to recover your data. To get started, you'll need a computer (Windows or Mac) with the most recent version of iTunes software installed. After you've set up your PC and iPhone, follow these steps:

1. On your PC, launch iTunes.
2. Use the USB cord that came with your iPhone to connect it to your computer.
3. To continue, input your device passcode or touch the Trust This Computer option on your iPhone display if prompted.
4. When your iPhone SE appears in iTunes, choose it. If it doesn't appear in iTunes, use these methods to force it to restart:
5. At the same moment, press and hold the Home and Power buttons until the Recovery Mode screen displays. When you see the Apple logo, don't let go of the buttons.
6. When you're given the choice of restoring or updating, choose Update first. If you do so, iTunes will try to restore iOS without destroying your data.
7. Otherwise, use iTunes' Restore Backup option to restore to an earlier iOS backup. Locate the iOS backup file you wish to use, then complete iOS by following the onscreen prompts.

Wait until iTunes has completed downloading your device's software. Please be patient as it may take a few minutes to complete. If the procedure takes more than 15 minutes, your iPhone will exit recovery mode, and you'll have to repeat the instructions to enter recovery mode on your iPhone SE. After your iPhone reboots, make sure to leave it connected and wait for it to sync with your computer before disconnecting.