I just had used my iPhone moments ago. When I hit home button to get to the lock screen, nothing happened. I thought I hit the button in a spotty area, so I did it again, and again. Seemed like the phone was off. Then I tried holding the hold button to start it, nothing. Then I thought, maybe it's not actually off, but still on, just locked up. So finally, holding down both home and hold forced it to restart. Thank goodness, for a second there I thought it suddenly died. So if you think your's is dead, it just might be locked up with the screen off, and using home and hold will force it to restart. I just hope not many of us will experience crashes while it's sleeping, making it look dead.