The iPhone is a multifaceted smart phone that Apple first released in 2007. The phone is capable of running several apps, checking email and playing music in addition to allowing users to make and receive calls. If the iPhone starts malfunctioning and will not turn on, there are several methods for troubleshooting the problem to get the phone back to proper working order.
If the iPhone will not power on, make sure the battery is charged. Start charging and wait 10 minutes before trying to power it on.
If the iPhone is fully charged and still not turning on, try a hard reboot. Press the "Home" and "Power" buttons simultaneously and hold. The reboot process should start. You can tell the process has started when the Apple symbol appears on the screen.
If the iPhone still does not power on, try connecting the iPhone to the computer using the iPhone USB cable. ITunes should recognize the iPhone and power it on.
Contact Apple.com/support/iPhone. Enter in the serial number of your phone and a description of the problem. Apple support will then give you a number to contact if the problem is still not resolved online.