Not the usual topic for this blog, but it may save you a few hours of trying to find what went wrong with your office 2007.
I was opening word 2007 to try to edit a document when I suddenly noticed that the mouse doesn't work in the editor window. I could click the ribbon, buttons and menu but as I said I couldn't mark any text or click in the editing area. Not to mention that Word crashed everytime I tried to close it.

Naturally, the office diagnostic didn't find anything wrong so there I went trying reparing, uninstalling stuff I installed in the last few days, blaming the anti-virus, Vista SP1 RC and whatnot.

 I finally found the answer in http://support.microsoft.com/default.aspx/kb/921541 . The kb article suggest several options. Basically all I had to do is delete HKEY_CURRENT_USER\Software\Microsoft Office\12.0\Word\Options\Data and let Word rebuild it.

As the kb article says " If Word starts and works correctly, you have resolved the problem" :) (and saved yourself a few hours)