From a licensing perspective, it's legitimate. Some people have reported
trouble, typically with retail editions.
Paul Thurrott provides excellent guidance through the issues that folks have
He also weighs in on the clean install vs. in-place upgrade topic:
> -----Original Message-----
> From: Technology Discussion at UVM [mailto:[log in to unmask]] On
> Behalf Of Alison Pechenick
> Sent: Wednesday, February 03, 2010 1:30 PM
> To: [log in to unmask]
> Subject: Re: Upgrading to W7 (was: Windows 7 Pro vs Enterprise)
> Not sure if this observation fits your remarks here, but please note
> that if, for some reason, a machine presently has Vista Home, you
> can't upgrade to 7 Enterprise. Upgrade has to match existing edition.
> Quoting Geoffrey Duke <[log in to unmask]>:
> > * A system must have some version of Windows purchased with it. Our
> > Agreement covers upgrades to existing Windows OS. Buying a system
> with Linux
> > disqualifies that system, and you need to buy a Full (i.e., non-
> > Windows license for the computer, preferably through the Microsoft
> > program via the Computer Depot.