I have activated two installs already and after moving from xp to 7 would be my third. I didn't want to just try it because I have not purchased windows 7 yet and would prefer not to if my copy of office would not be activated. Also, I tried calling Microsoft once before and was hung up on by the automated system 3 or 4 times so, I'm not all that excited about the prospect. I purchased a netbook with xp installed about a month or two ago and that is when I installed and activated office for the second time.