My ipod was recognized before but now when im trying to sync it wont recognized my ipod

1. Reboot computer

2. Reset iPod. Hold the Sleep and Home button down for about 10 seconds until you see the Apple Logo.

Try:

- iOS: Not responding or does not turn on

- Also try DFU mode after try recovery mode

How to put iPod touch / iPhone into DFU mode « Karthik's scribblings

- 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.

- If still not successful that usually indicates a hardware problem and an appointment at the Genius Bar of an Apple store is in order.

Apple Retail Store - Genius Bar