I strongly advise against installing from a bittorrent image -- there is simply too much danger of picking up viruses and malware, not to mention that there's no assurance that what you get is a release package, as opposed to one of the betas and RCs. Microsoft has leaked the download links for Vista retail -- of course, you still need a valid key, but you can get the software straight from the horse's mouth. If you look at the first step in the link I posted above, you'll see the links to the Vista download from Microsoft.