Trying to open word documents - windows installer stops it happe

[statty45]

I have a 2 year old machine running Vista and office 2007. Recently. when I
try to open a word doc I get the following message from Windows installer.

C:/users/owner/document

This update package could not be opened. Verify that the update package
exists and that you can access it or contact the application vendor to verify
that this is a valid windows installer update package

everything worked fine until this started around 2weeks ago can anyone help
please