Downgrading from Windows Vista Ultimate to XP Professional RRS feed

  • Question

  • Hi,

    I would like to downgrade from Windows Vista Ultimate to XP Professional, I have a OEM Product key as well as a Product key on the side of my tower (I think), I also have a Windows XP Home Edition Product key but I need Professional because I'm using 2 CPU's.

    I do not have a Windows XP Professional Product key though, so is it still possible to downgrade Windows Vista Ultimate to XP Professional? if so, how?


    • Moved by Carey FrischMVP Sunday, February 6, 2011 4:05 AM Moved to relevant forum category (From:Windows XP Genuine Advantage Validation Issues (Windows XP))
    Sunday, February 6, 2011 3:14 AM


  • Hi,

    OEM downgrade rights for desktop PC operating systems apply to Windows Vista Business and Windows Vista Ultimate as stated in the License Terms. Please note, OEM downgrade versions of Windows Vista Business and Windows Vista Ultimate are limited to Windows XP Professional (including Windows XP Tablet PC Edition and Windows XP 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 Windows Vista Home Basic or Windows Vista Home Premium.


    For more information, please refer to the following site:




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    Wednesday, February 9, 2011 9:37 AM