4 ways to fix a 'dead' iPhone
We show you how to revive a dead iPhone
If you see the red empty battery icon, your iPhone will not be able to reboot until there is a certain amount of charge in the battery.
Plug the iPhone into a high-powered USB source such as the mains charger or one of the main USB ports on a computer that is plugged in.
If you see the red section of the battery image flash three times and then the screen goes black, it means that iPhone is not receiving power to charge.
If the iPhone 3GS battery is totally drained you may not see the battery recharge image for several minutes. If the display is blank when you plug it in wait a while to see if the image appears.
To reboot or restart your iPhone press and hold down the Sleep/Wake button on the top until the red slider appears. Slide it across to turn it off. Repeat the process to turn the phone back on.
If the iPhone is frozen and can't be restarted in the normal way do the following.
Press and hold the Sleep/Wake button and the Home button simultaneously for at least 10 seconds. The red slider may appear and the screen may dim but don't release the two buttons until the Apple logo appears.
Click on Settings then General then Reset All Settings
This will reset all the settings to the factory defaults. None of the data or content on the iPhone will be deleted.
4. Back up and Restore
If all else fails, you will need to back up and Restore your iPhone.
First make sure you have upgraded to the latest version of iTunes. Then connect your iPhone to your computer and select it when it appears under Devices in iTunes.
If you haven't performed a Sync recently do so now to make sure all your contacts, photos and videos are in sync.
Click on the Summary tab and then click Restore. If you haven't already backed up your iPhone 3GS you will be prompted to do so now. This will back up all the settings on your iPhone.
At the next prompt click on Restore. If you have completed all the steps above you need not worry about your data and settings.
Wait until your iPhone completes the restore process and returns to the Home screen.