Problem with Microsoft Word

I have a user that can?t get MS Word to open documents from a mapped drive. When they click the document, Word opens but doesn?t display the document. If they go into File ? Open and browse to the document it opens just fine. I have un installed and reinstalled the entire office suite, and it changed nothing. If another user logs on to the same machine there is no problem at all. This is a system on a domain running XP Pro with Office XP small business on it.
Any ideas?