If your Apple iPhone screen is frozen or locked up, it’s not fun. Normally you can simply pull a battery from a device if it locks up. The iPhone doesn’t have a removable battery though. Instead, you’ll have to try these options.
Press and hold the Home button below the screen for at least six seconds, until the application you were using quits.
Try to Power Off
If a Force Quit does not work, turn the iPhone off and turn it on again. Press and hold the Sleep/Wake button on top of iPhone for a few seconds until a red slider appears, and then slide the slider to power the device off. Once powered down, press and hold the Sleep/Wake button to turn the device back on.
Press and hold both the Sleep/Wake button located on the top of the screen and the Home button for at least ten seconds, until the Apple logo appears. You may have to hold the buttons down for up to 20 seconds before anything happens. Afterwards, your device should restart and return you to the Home screen.
Hopefully, one of these options have worked for you and your Apple iPhone is now working again. If not, you may need to try a restore using iTunes, which will wipe all data from the device. Data can usually be re-synced from your computer once restored.
Oh, and if your iPod Touch or iPad is frozen, you can try these same steps to fix a frozen or locked up device.