Restarting your computer is often the solution when your iPod fails to sync with your iTunes music library. But if this fails, there are other troubleshooting steps to take.
Recharge your iPod via a USB cable connected to your computer or AC adaptor.
Click the help menu in iTunes and check for updates. Follow the onscreen prompts to download and install the latest version of the software. Open the new version of iTunes. Click the name of your iPod in the source list and check for updates under the summary tab to update your iPod. Attempt to sync your iPod with iTunes.
Slide your iPod's hold switch to the hold position and then to off. Press and hold the menu and centre buttons simultaneously until the Apple logo appears to reset your iPod. Open iTunes on your computer and reconnect your iPod to try to sync it with iTunes.
Close iTunes and make sure your iPod is disconnected from the computer.
Click the 'start' button. Click 'run' if using Windows XP. Type 'services.msc' in the run box in XP and in the search box in the start menu in Windows 7 and Vista. Press 'enter.'
Scroll through the list and double-click on 'iPod service.' Click the 'stop' button and leave the properties window open.
Connect your iPod to the computer. Open 'my computer' or 'computer' and look for your iPod listed in the devices with removable storage section.
Click the 'start' button in the iPod Service's properties window. Open iTunes to attempt to sync your iPod. Close the iPod Service's properties window once your iPod has finished syncing.
Double-click the name of a song in the iTunes program that failed to sync to your iPod.
Click 'yes' or 'locate' to the message asking you if you want to locate the file.
Navigate to the folder or directory location where the song is stored on your computer. Double-click the song file to select it and add it back to iTunes.
Reconnect your iPod to the computer and open iTunes to restart the syncing process.