I would suggest that you put your iPod into DFU Mode to restore it.
In case you don't know how to do this :
* Plug your iPod to your computer (PC or Mac, it doenst really matter)
* Press both the home and power button until it shuts down.
* ONLY RELEASE the power button, keep the home button pressed for approximately 20s. Your computer should then prompt that it has detected a device on recovery mode and will suggest you to restore it. Just do so.
Hope this helps !