Before you chuck your iPhone into your electronics junk drawer because it won't turn on after resetting, you should charge the device's battery. While your device requires little battery life to turn off, powering back on uses energy and may not have enough power to return your iPhone to its home screen. The phone displays a pop-up alert when it reaches 20 percent and 10 percent of its battery life, and displays a red sliver of color in the battery icon on the home screen. If the iPhone still won't turn on after charging, it needs professional repair at your local Apple store.
Insert the connector cable into the iPhone's 30-pin port found on the bottom of the device. Insert the cable's opposite end into the power adapter, and plug the power adapter into an electric outlet. Charge the iPhone for 10 minutes. The iPhone will automatically turn on when it has enough power to start up. Charge the phone for two hours, which restores the iPhone's battery life to 80 percent.
Press the "Home" button on the front of the iPhone to check the status of the battery. An image appears on the screen to display the amount of battery life. Remove the cable from the power adapter and insert it into your computer's USB port. If the iPhone does not start the iTunes program, proceed to the next step.
Contact your local Apple store to set up a service appointment (see Resources).