...It depends on which version of Vista you have installed.. You may or may not have downgrade rights. "Business" and "Ultimate", then yes you have downgrade rights. "Basic" & "Premium" OEM installations generally don't include such. As a result, The downgrade media must be supplied to you from the end user and must come from a legally licensed version of Microsoft retail, OEM/System Builder, or Volume License channels.(Usually it's a "full" version of XP SP2 PRO.)
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Q. Can I downgrade my OEM version of Microsoft Windows Vista Business to Windows XP Professional?
A. Yes. OEM Downgrade Rights for desktop operating systems apply to Windows Vista Business & Vista Ultimate as stated in the License Terms. Please note, OEM downgrade versions of Windows Vista Business and Vista Ultimate are limited to Microsoft Windows XP Professional (including Tablet PC Edition & x64 Edition). End users can use the following media for their downgrade: Volume Licensing media (provided the end user has a Volume Licensing agreement), Retail (FPP), or System Builder hologram CD (provided the software is acquired in accordance with the Microsoft OEM System Builder License). Use of the downgraded operating system is governed by the Windows Vista Business License Terms, and the end user cannot use both the downgrade operating system and Windows Vista Business. There are no downgrade rights granted for Microsoft Windows Vista Home Basic or Home Premium.
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See the link below:
http://72.14.253.104/search?q=cache:9T-J3mq3I5QJ:download.microsoft.com/download/f/5/5/f5573dbc-e4d9-464f-953c-4eacea2a38c1/VL_downgrade_rights.doc+XP+downgrade+license&hl=en&ct=clnk&cd=2&gl=us
Hope this helps.
Grif
I am the network admin for a small medical office. We are purchasing a new computer and it comes with Vista already installed. The software we run does not run under Vista yet, so we will need to downgrade to XP. My question is this... We don't have any XP cd's around so we will be purchasing a copy. Can we buy the upgrade cd or do we need the full version? I am thinking that we should be ok with the upgrade, but I just need to bounce this off a fresh brain. And, no, we can't just order a machine with XP on it. The office manager insists we buy a Dell, and the budget for the new machine is somewhat tight.
Thanks in advance.

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