"Microsoft has decided to enhance the End User downgrade facilitation options available to OEMs for downgrading systems with Windows Vista Business or Ultimate editions to Windows XP Professional. In addition, Microsoft will allow limited End User downgrade rights from Windows 7 Professional or Ultimate editions to either Windows Vista Business or Window XP Professional.
Yes, it's a little confusing, so we are here today to lay it all out for you. Our intrepid source at Microsoft has given us new updates on Microsoft's policies on Windows 7 and Windows Vista Downgrade Rights. Let's take a look at what these new Downgrade Rights entail."
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips