When you buy a PC with Vista Business, you have certain downgrade rights. Some people prefer XP as its familiar and doesn't take up as many resources as Vista does.
You can view the Microsoft Downgrade Rights here
FAQs
Q.
Who can install the downgrade software or reinstall the original software?
A.
An OEM (when authorized by end user), or the end user.
Q.
Can I ship media for the downgrade software system as well as most recent version they are using to downgrade from?
A.
No - downgrade media is provided by the end customer.
Q.
What about product activation? When a previously licensed version of Windows XP Professional is used for the downgrade, won't activation fail on the new PC?
A.
When an end user is using their downgrade rights offered under the License Terms in Windows Vista Business and Ultimate versions and they use both Windows XP media and a product key that was previously activated, they will be unable to activate on-line over the Internet, due to the hardware configuration change when installing on the Vista system. In these cases the end user will be prompted to call the Activation Support Line and explain their circumstances to the Customer Service Representative. Once it is determined that the end user has a valid Vista Business or Ultimate license, the Customer Service Representative will help them activate their software.
Q.
Can end users return to Windows Vista Business or Windows Vista Ultimate software after they downgrade?
A.
Yes. End users who downgrade may reinstall the original software when they are ready to migrate. For example, an end user who downgrades to Windows XP Professional may later return to Windows Vista Business software provided that the end user deletes the Windows XP Professional software from the PC.
Q.
How do end users reinstall the original software after downgrading to a previous allowed downgrade version?
A.
End users must use the original OEM media or recovery software on the hard disk that was included with the PC for reinstallation. The downgrade software must be deleted from the hard drive before the original software is reinstalled.
Q.
Where do customers get the CD to install the downgrade software?
A.
End users must use a legally licensed version of the specified previous version of the Windows desktop operating system to install the downgrade software. The downgrade software may be from the retail, OEM/System Builder, or volume licensing channels.
