Hi - Had a question for people here, as I'm not able to find an answer anywhere else. I have a copy of MS Office:mac 2004 (student & teacher edition) that I plan on selling to another individual; however, I have registered two of the three available product serial keys. If I plan on selling this item - how do I unregister those serial keys under my name? Do they just transfer over? Will the buyer have any difficulty with installation using the keys? (Hopefully I'm making sense...) Appreciate the help.