What surprises me is that, even though Vista has been around for a while, I'm yet to find absolute clarification on stuff like this!
Fire Wizard, I appreciate what you're saying if the software had come pre-installed on a bought machine, but I bought the software independently from any hardware, and have not yet activated it (as Ice on Fire suggested, have I accepted the EULA yet?)
I'm basically looking to move the copy, that I've only had installed for a couple of weeks on my main PC, to a media centre machine to make better use of the Media Centre software.