Hi. Itunes help desperately required.

I recently managed to break my external hard drive and lost all my tunes that were saved on there. After some kind advice on here I've managed to rip all the tunes from my ipod and stuck them back on a new external hard drive. However i tunes seems unable to locate them unless I click on each track and opt to find it on the external hard drive. My settings have the correct folder selected.
Does any body have some great idea how to solve this as this is doing my head in?
Thanks