Problems Connecting My iPhone to a PC
When you connect your iPhone to your computer, the two should connect automatically. When they are connected, the iPhone icon will appear on the computer letting you know the two are "speaking" to one another. If you don't see the icon in the iTunes program, there may be connection problems. There are several things you can do to check the connections.
Check the USB connections between the iPhone and the computer. The iPhone only has one USB connector, which is at the bottom of the device. Make sure the USB is plugged directly into the iPhone. The other end of the cord plugs into a computer. If it's already plugged into one USB port in the computer, but not functioning, try plugging it into a different port. On most desktop computers, USB ports are on the front bottom or back of the computer. For laptops, USB ports may be on either side of the keyboard or back of the computer. Make sure the USB connector is plugged all the way into the computer.
Low battery power on the iPhone may be contributing to your connection problems. If this is the case, it can take up to 10 minutes before the PC will recognize the device. Make sure the iPhone's battery indicator is not red and flashing, which would mean the battery is about to die. Charge the iPhone using the power adapter before trying to establish a working connection between your device and computer.
Restart iPhone and Computer
Restart your iPhone by pressing the "Sleep/Wake" button twice. Apple also recommends disconnecting your iPhone from the computer by removing the USB cable connecting the two devices. Try restarting your computer and then reconnecting the iPhone. If the iPhone and computer are still not connecting with one another after a restart, you may need to reset the iPhone. You can do this by holding the "Sleep/Wake" and the "Home" buttons at the same time. Continue holding down both buttons until you see the Apple logo on the screen. The logo takes about 10 seconds to appear, but when it's visible, the device is reset.