WORD problem in dual-boot XP/Vista

Having a Dell XP Pro on C:, I just clean installed Vista on D: and then Office 2003. All Office applications work OK except WORD. When clicking a .document it briefly shows an ‘Installing etc.’ window before it reluctantly starts and shows the document. Excel and PowerPoint start instantly.
Also WORD does not appear in the New menu.

It feels as a conflict with WORD 2003 in XP on the C: drive.

Restoring, uninstalling or reinstallin give no relief.

Any help available?