Thanks for the extra information.
Sometimes this can be fixed by re-setting the default file associations in Vista
AFTER the Office installation: Control Panel . . . Default Programs . . . Associate
a file type or protocol . . . and set the file associations you need. I've read that
if the right associations are already set, you need to set them to something else
(eg notepad, whatever) and back again.
It seems this is a common problem with Office 2007 installations :-(