4882 Views 2 Replies Latest reply: May 13, 2009 7:35 PM by modular747
Try a forced (DFU) restore:
Connect the phone to iTunes.
Simultaneously press the home and sleep/wake buttons until the Apple icon appears (ignore red slider) and the continue to press the home button alone until iTunes sees the phone is restore mode.
Restore as a new iPhone.
If it sill won't activate, you may have a defective phone or SIM, or AT&T dropped the ball on your account and didn't enter your new phone ID. Contact them first.