When you synchronize your i Pod with Apple's i Tunes software, it will delete all the music content in your i Pod.To resolve this, connect your i Pod to your system and click on the i Pod icon.Just a matter of copying and pasting, it’s that simple.
Use of any content or images without expressed permission is not allowed, although links to any page are welcomed and appreciated.
However, moving the i Tunes library to another computer is not as difficult as it seems, since you have the original (host) computer up and running, so you can get stuff out of it.
Apple has detailed instructions for that, so have a look at them.
Select 'manually manage music' and create a playlist by adding the songs you want in your i Pod. Select the created playlist and click on Auto fill, which adds all the songs to your i Pod without deleting the other songs in your i Pod.
This document, titled "Syncing i Pod without erasing other songs," is available under the Creative Commons license.