I have XP and I can run Office 2007 just fine. Any when you upgrade to XP, you will be able to install on Vista too. Usualy the licenseing for Microsoft will support up to 3 computers or operating systems at the same time. I dont know how many computers you are running Office on from that CD, but if you dont want to waste one of your office licences, just go ahead and uninstall it off one computer or OS and install on another. You can only have Microsoft office on three computers at the same time. Thats all. I hope this helps some.