You can post or update any article in the wordpress site through the MS word 2007. You don't need to login at the admin area of your WP site. Here are the steps.
Steps :
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1. Logged into the admin area of your wordpress site. Make sure that the Atompub and xmlrpc has been enabled. These options are at "settings" >>Under writing.
2. Open the MS word 2007.
3. Edited a new page.
4. Clicked on "Office button" which is at the top-left corner.
5. Go to publish >> clicked on Blog >> Clicked register now option
6. Entered the URL : http://underlore.com/TBA/xmlrpc.php
username : username of WP(admin)
password : password of WP(admin)
7. Clicked on OK. that's it.
Have a nice day :)