Bogus addresses in pop up list

Exchange Server 2000 with AD in native mode
Client – Windows XP with Outlook 2002

Problem
Client types 3 characters in email address of a new message and a pop up list is displayed with recent names/email addresses to choose from. One of those popup names is incorrect but does not appear in any address lists such as the network GAL or the User’s PAB or Contacts
How do i remove the incorrect name from these popup lists?

The above senario also happens on 1 Win95/Outlook98 machine. The offending email address was legitimate some months ago but has subsequently been removed but it still shows in the popup list.
It appears as though it is a client issue as others are not affected.

Any help would be appreciated