I have had a similar problem but with XP. I had a HD go down so had it replaced in the middle of last year (2009). Everything was fine, then I had one of the first Tues in the month security updates and straight afterwards it says the copy of Office is not genuine. So I dont think it is just Vista that is the problem. There must be something written to the original HD and when it is changed it thinks it is not genuine. This is really annoying when you actually shell out good money for the software rather than use a prated copy.