I was just wondering whether there is any difference between MSDN version and Retail/VOL version of VISTA (or any other OS) . I am not talking about the difference in the licensing or activation keys. Suppose if i have (i dont!) a MSDN version dvd and RETAIL/VOL dvd will they exactly the same,in case of content? Is MSDN version realy a RETAIL/VOL version but just called MSDN version because of the way.....? I have seen different ISO images of a single OS (say VISTA), same build number but ISO images have different MD5 hashes. Everything claims to be genuine and untouched and the MD5 hashes, when googled produces hits (all from different sites and all have the same decription) How come that? No ISO images in my collection maches with the ones found on official MSDN server. (MD5 hashes on MSDN site). please help with a detail answer.