The row where number 4,5,6 is located or where C, +-, /, * are located when calculater is opened on my iPhone 3G does not respond when pressed. I have reset all settings, restored to original factory settings, changed the digitizer and LCD + IC, to no avail. Sometimes it works but most times it is non-responsive to touch. Do I have a hardware/software problem. Any suggestions would be appreciated. Actually I have lost patience and am on the verge of throwing the phone away.