I just faced this problem 2 days ago, when my 3GS iPhone stopped working and reboot, it doesn't fully reboot that i dont need to unlock my SIM,just retarts with the apple sign, and then comes back to the home screen. When i tried to charge it i kept having difficulties, that even when it's plugged with the charger it gives a sign we have when the battery is full. Now it keeps rebooting somehow like every 5 minutes, or when am in the middle of doing something, whether an application or a phone call, even listenning to music. Does any one had the same problem before, or has an advise for this issue? Best and thanks for all in advance.