This is interesting: How to install a Vista upgrade on any PC.
Microsoft is running an unadvertised sale on Windows Vista. For the price of an upgrade edition requiring an existing copy of Windows, anyone can have a stand-alone version of Vista that will run on any PC. Indeed, the upgrade editions are full versions, simply waiting to be told to install themselves regardless of what OS is currently on the system, if any. The trick is all in how you interact with the setup program.
Microsoft MVP Marc Liron was kind enough to explain the procedure in this recent article, and we merely set about duplicating his results. Which we did, with an upgrade version of Vista Home Premium, and found that Liron's instructions worked like a charm.
One theory is that Microsoft is well aware of it. And here's why:
Microsoft has made a colossal mess of Vista upgrades with five separate editions that are each tied to specific previous editions of Windows, and very little in the way of guidance, except for a dysfunctional Upgrade Advisor. Few other companies would wager a product launch on a lame gimmick like that.
So when you think about it, the sensible thing would be to anticipate endless complaints from consumers stuck with the "wrong" update edition, and to try to placate them with the promise that if they would just part with all of their data, their installation problems can be solved.
http://www.theregister.co.uk/2007/02/12/cheap_vista_for_everyone/
