A question about using the product keys for Office. Currently all three keys of my copy are in use, (myself, sister & mum,) but i'll be a getting a new MacBook soon to replace my iBook. If i stop using Office on the iBook, can I install Office with the same product key on the MB? If so, is it just like a switch, (i.e. once installed on MB, automatically cancels the iBook version,) or do I need to get stuck in transferring/deleting files?