How to delete duplicate contacts folders in Office XP?

Hi,
I have a client who has Office XP and when they go to create a new email and
they click on the "To:" button, an error is reported with the contacts, and
they need to select the second "contacts" option from the top right of the
page "Show names from" section.

I have seen this problem before with Office 97 and knew how to remove the
corrupted Contacts file/folder and leave the correct one in place. But I
can't seem to find how to do it for Office XP.

If my explanation needs better explaining, just say so.

Any help is appreciated,
rob.
--
MCSE 2000