Office 2007 setup fails

I have been switching between Office 2000 and 2007. All worked fine except
Word run some kind of setup every time when switching. Last time I started
Word 2007 the setup failed. Now I can run Office 2000 but I can’t uninstall,
repair or reinstall it.

When I start some of the 2007 apps, I get the message:
“Microsoft Office (program name) has not been installed for the current
user. Please run setup to install the application.�

When I run 2007 install it fails with message:
“Setup did not complete successfully. We are sorry for the inconvenience.
An error has occurred during the installation, and setup was unable to
complete.�

I can’t uninstall, repair or reinstall it. So, my two Office 2007 licenses
(one eng professional and one swedish home) are useless.

What to do?