I can't think of anything else but would try the following:
- Make sure you have your installation disk for Office.
- Uninstall Word. If you haven't tried a Repair, try that first.
- With Word uninstalled search your hard drive for the built-in building blocks.dotx file. Search in hidden and system files as well.
- Rename any file you find if you have any custom building blocks. If you have no building blocks that you created, delete the files.
- Reinstall Word.
It should not take that and uninstalling/reinstalling Word has no effect on this problem if the faulty building blocks file is not dealt with.