Try one or more of the following:
> Restart your computer
> Uninstall & Reinstall iTunes
> Reset Your Device (won't erase anything)
> Go to My Computer (windows xp) or Computer (windows Vista & 7) and see if your device shows there.
> Restore your device completely (will erase everything)
- Try another cable. Some 5G iPods were shipped with Lightning cable that were either initially defective or failed after short use.
- Try another charging source
- Inspect the dock connector on the iPod for bent or missing contacts, foreign material, corroded contacts, broken, missing or cracked plastic.
- Make an appointment at the Genus Bar of an Apple store.