If the mp3's etc are all still on your PC/Laptop and not deleted as well, you jut need to tell iTunes where they are, let it sort itself out for half an hour or so whilst it rebuilds it's catalog, then re-synch with your ipod.
If you're not sure, and can wait until I get back from Manchester tomorrow night I can take control of your PC using this..http:\\
www.gotoassist.com .and look at it for you.
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