How to Fix an iPhone That Freezes
When you launch applications, type, or play games, sometimes your iPhone freezes and becomes unresponsive. When you press any buttons, your device doesn't respond. This can usually be very annoying especially if you are in the middle of something. Without damaging your iPhone, you can fix the freezing issues and restore your iPhone back to working condition with basic troubleshooting steps.
Press and hold the "Sleep/hold" button for a few seconds, and then release. You see the red slider. Do not drag the red slider.
Hold down the "Home" button for about six seconds. Your device returns to the home screen. Move to the next step if it doesn't return to the home screen.
Press and hold the "Sleep/hold" button again until the red slider appears. Drag the red slider to turn off your iPhone. Wait a few seconds, and then press the "Sleep/hold" button again for a few seconds until the Apple logo appears.
Press and hold the "Sleep/hold" button and the "Home" button together for at least 10 seconds if you are still having problems. This resets your iPhone.