- Press and hold the Sleep/Wake button until the red slider appears.
- Drag the slider.
- Press and hold the Sleep/Wake button again until the Apple logo appears.
This will delete all data off the phone. If you have your iPhone backed up on your computer through iTunes, etc., you can perform a Restore using your computer to get your data back.
- Press and hold the Home button below the screen and the Sleep/Wake button on top of the iPhone simultaneously.
- Continue holding both buttons, ignoring "Slide to power off", until the iPhone shuts off and begins to restart.
- You may let go when you see the silver Apple logo.