Jag har äntligen löst det. Jag fick svaret på Macfixit.
1. Use a utility like file buddy to make the file "OfficePID" visible. This is usually located in /Applications/Office v.X/Office/OfficePID
2. Move this file to the trash. (or use terminal.app if you are UNIX savvy)
3. For each user who has run office, remove the following preference files:
Carbon Registration Database
Office Registration Cache X
Microsoft Office Settings (10)
These are all located in $HOMELibraryPreferencesMicrosoft
4. Re-launch any of the Office v.X apps and you will prompted to re-register them. Make sure you have your serial number handy at this point.