If your copy of Office 2008 was installed with an invalid product key, or if you mistakenly used the same product key to install Office 2008 on more than one computer, you must remove the invalid product key and enter a valid product key to use Office 2008.
1. In the Finder, select /Applications/Microsoft Office 2008/Office/OfficePID.plist, and then on the File menu, click Move to Trash.
2. Select /Users/username/Library/Preferences/Microsoft/Office 2008/Microsoft Office 2008 settings.plist, and then on the File menu, click Move to Trash.

-YOU WILL BE PROMPTED to RE-Enter your license, as used before the Uptade