Have you tried resetting your iPod?
Press and hold the
Menu and
Select (center) buttons together until the Apple logo appears on your iPod's screen.
Do this several times, and see if there is any difference.
Try putting your iPod into Disk mode, and connecting it to your computer. For more info, see this:
Putting your iPod into disk mode
Also, see these troubleshooting steps:
The Five R's
-Kylene