If you leave Word 2007 (and possibly Outlook 2007) running overnight during the time Automatic Updates (AU) pushes down a patch to your machine and needs to do a reboot and you experience unusual behavior in your Word 2007 application thereafter, it may be related to corrupted Word Data Key.

While the troubleshooting for a corrupted Word Data key is the same since Office 2000, the discoverability and or conclusion that it is your Data key that is causing your symptoms, may not always be the first thing you think of.

We're working on ways to best document and help make our KB articles more discoverable.

In the meantime, the link to the currently available KB article for resetting your Word "Data" key is here:

http://support.microsoft.com/kb/822005/en-us