It is easy to remedy this problem, as long as the user has access to his or her iTunes account on the Mac or PC that they originally synced their iPods. Here is a step-by-step guide to unlocking your iPod.
1. Firstly, open up iTunes on the computer you last synced your iPod to, then plug the iPod in via the USB data cable. Click on the iPod icon that with shows up in the 'Devices' section side window, so you can see the iPod info in the main window.
2. If you have not transferred any purchases on your iPod to your main computer, then please do so first before going any further. Go to the main menu under 'File' choose 'Transfer Purchases from "User iPod". This transfers any items you've purchased via the iPods iTunes Store, back into the original computer, as you can't redeem any lost purchases.
3. In the main window summary tab, under the section called 'Version', you'll see a button called 'Restore'. Click on this button to reset your iPod to its default factory settings. This will overwrite your iPods operating system software and remove any passwords. This may take quite a while, depending on the size of your iPod’s hard drive.
4. Once the iPod has been restored, you can then re-add all your songs, albums and playlists. To do this, go to the music tab and choose what music you'd like. You're now ready to go.
It is a good idea to write down a hint or reminder for your password elsewhere, so you do not forget it again.