Try restarting your iPod touch by holding down the on/off and the home buttons at the same time until you see the Apple logo. If you are still having problems take a look at this link, http://support.apple.com/kb/ht1808
Next try the remaining items of:
- Also try DFU mode after try recovery mode
- If not successful and you can't fully turn the iOS device fully off, let the battery fully drain. After charging for an least an hour try the above again.
- Try on another computer
- If still not successful that usually indicates a hardware problem and an appointment at the Genius Bar of an Apple store is in order.