Answer to: Why is my touch screen not responding?Had a locked screen this morning on my 3GS. After a cup of coffee and a quick web search on an Apple forum I found the simplest fix to try first. Hold down the power button and the home button below the touch screen until the screen goes dark and comes back with the Apple logo. Then leave it alone until the password login screen appears and is active. Then log in. It actually took me two full reboots before the iPhone seemed to be running without any problems. Seems to me a software reboot is by far preferable to doing barnyard mechanics inside the phone.