This support document also provides additional information on locking and unlocking the iPod. According to Apple, if you have forgotten the code, you can unlock the iPod by doing the following:
Connect your iPod to the primary computer you use it with (the first one iPod synced with), and open itunes. When you disconnect iPod from the computer, it will no longer be locked.
If you can't unlock iPod using either [the code or connecting it to the computer you use to manage its songs]. . . you can restore your iPod to factory settings using iPod Updater. Please note that this will erase all data on your iPod. After wards, you can add your music and data back to your iPod.
If you want to change the primary computer that your iPod is associated with, do this:
1. Restore your iPod. Warning: The restore process cannot be undone. All of your songs and files will be deleted. Always make a backup of your important data.
2. Connect your iPod to the computer that you want to be the primary computer.
3. Open itunes and synchronize.
Apple also notes that company "representatives cannot unlock an iPod if you forget your combination. If you can't unlock your iPod and you don't have access to the primary computer, your only option is to restore the iPod, which will erase all music and data."
the same thing happened to my friend so the only way was to re store it
look at the website below