The next time an Office component wants to re-install itself, let the process complete. Then, open Event Viewer and look in the Application log for a cryptic message similar to this:
Event ID: 1001
Event Source: MsiInstaller
Description:
Detection of product '{90280409-6000-11D3-8CFE-0050048383C9}', feature 'WORDFILES'
failed during request for component '{8E46FEFA-D973-6294-B305-E968CEDFFCB9}'
followed by:
Event ID: 1004
Event Source: MsiInstaller
Description:
Detection of product '{90120409-6000-11D3-8CFE-0050048383C9}', feature
'ProductFiles', component '{66CD2C91-2A15-4DA4-BBD2-5EC1075F3C0E}' failed. The
resource 'HKEY_CLASSES_ROOT\.pip\' does not exist.
The message will contain the name of the Office program that re-installed itself. In the above example, it was Word.
If you see that type of Warning, your problem is insufficient registry permissions. There is a solution, but it's complicated to implement. Post back if you are seeing the Event IDs described above.
Daddy