After many failed attempts and befuddled helpers, I finally received a solution from Dell which has worked. It enabled me to uninstall Office (which the problem with Enterpriseww.msi did not allow) and then reinstall properly.
Here is the advice:
a. download the windows installer utility for the following link:
b. Click the Download The Windows Installer Cleanup Utility Package Now" link in the More Information section.
c. Save the utility to your desktop.
d. Double-click msicuu2.exe and follow the onscreen instructions to install.
e. Choose Start > Type Windows Install Clean Up to start the Windows Install Clean Up utility.
f. Now choose the office 2007, and choose Remove.
After performing the above steps use the Office 2007 CD to install complete package.
This returned my Office suite but now I'm having the same problem with OLAddin.msi! Just waiting for Dell to advise.