Apple's iPhone touch screen feature provides an intuitive user experience that many people find useful; however, there can be problems with the screen being unresponsive. There are several do-it-yourself remedies you can try to correct this problem before seeking assistance from Apple.
Clean the Screen
Clean the iPhone's screen. Apple conveniently supplies a suitable cloth inside the box that came with your iPhone. If you use a sheet or film over the screen as a safeguard, remove this first before thoroughly wiping down the area. To prevent further debris accumulation, make sure to only use the iPhone with bare, dry hands. Moisture from water or lotion has been known to affect the touch screen's responsiveness.
Force Quit and Reset the iPhone
Force quit an application. A running application may freeze from time to time and can ultimately cause the screen to stop working. To resolve this, press the "Home" button located below the screen and hold it for at least six seconds. This makes the running application force quit and fix the screen problem, if that is the troubling factor.
If unfreezing your application does not work, the next tactic is to press the "Sleep/Wake" button located at the top of the iPhone and then hold it down for a few seconds. When the red slider emerges, touch the screen to move the slider across the display. Next, press and hold down the "Sleep/Wake" button again until you see the Apple logo.
Finally, if the above procedures are unsuccessful, reset your iPhone by completely turning it off and then on again. Resetting is the answer to many problems that occur. To do this, press and hold the "Sleep/Wake" button while simultaneously holding down the "Home" button. Do this for a minimum of 10 seconds until the Apple logo appears. Test the touch screen to see if the problem is resolved.
Contact Apple Support
If all else fails, your best option is to make contact with Apple Support using any one of the methods they provide. You can go to Apple's "Contact Apple Support" page and arrange an evaluation phone call or make a reservation with a local Apple Store to have your iPhone looked at. You may also call the Apple Store directly or simply drop by and go straight to the Genius Bar to make an appointment to get assistance.