on the mac, go to applications>utilities folder>ipod software updater and run the ipod updater
from there you will need to perfrom a restore. this will bring the ipod back to factory settings
on a peecee, go to all programs>ipod folder>ipod updater and again, run the restore via the ipod updater program
if you dont have any, or still cant find these...
www.apple.com/ipod/download will give you the most current version of the ipod updater for whatever your OS is