Apple's iTunes software contains mechanisms specially designed to sync with your iPod, allowing you to transfer music, videos and other media from your computer. If you find that iTunes does not recognise or allow you to access your iPod, then you cannot perform some of the device's most fundamental functions. Fortunately you can often resolve this problem without expensive maintenance, simply by doing a bit of troubleshooting and determining the cause of your connectivity problem.
Try resetting your iPod. Apple recommends this as a first step in troubleshooting an iPod not appearing in iTunes, since a quick reset will often restore functionality. If you use a click wheel iPod, hold down the "Menu" and centre buttons until the Apple logo appears on your screen. For the iPod Touch, hold your "Home" button and "Sleep" button simultaneously until the Apple logo appears.
Charge your iPod battery. If your battery has absolutely no power left, your iPod will often remain unresponsive even when plugged into iTunes. Try charging for three to four hours and then try connecting again.
Plug your iPod into your computer using a different USB port. Sometimes a failed connection can mean you have a faulty USB port, so try plugging your USB cable into a different port and see if the iPod appears in iTunes.
Verify that you have the latest version of iTunes. Visit the iTunes page Apple.com and check to see the latest version available. If you do not know which version currently runs on your computer, click "About iTunes." For Mac users, this option will appear under 'iTunes" on your menu bar. For Windows users, the option will appear under "Help" on your menu bar. Download the latest version of iTunes if necessary.
Reconfigure your iPod service. If running iTunes on a Windows computer, click "Start > My Computer > Manage," and select "Services and Applications." Under "Services," select "iPod Service" and click "Stop." Leave the window open and connect your iPod to your computer. When your iPod shows up on your computer, click "Start."
Reinstall iTunes. If simply updating iTunes does not work, you may have defective software. Try removing the program from your computer and completely and reinstalling it.