Outlook 2007 Installation Issues - Error during setup with no code

Trying to install a copy of Outlook 2007 with only Windows Mail running
(don't believe we ever had an older copy of Outlook)

I get the following: Microsoft Office Outlook 2007 encountered an error
during setup - but no other error code.

Have purchased clean copies of Home/Student Office 2007 and subsequently
Outlook 2007.

Have read previous threads but couldn't find earlier version of Outlook on
the machine. Has Microsoft Work.

Running on Vista.

Run out of ideas. Any suggestions will be appeciated