Not everyone has been going with Windows 7 as there are many companies who have standardized on Windows XP Pro and cannot migrate quite yet. Microsoft is to discontinue support on XP Pro SP3 in April 2014 but just try buying a copy. Usually after the first service pack we will see further adoption to the new OS Win 7.
If you must have Windows XP Pro, Stealth has limited inventory that is available on a first come first served basis. Keep in mind this is the original OEM License and media and must be sold with a PC. Call our Sales Associates to discuss; Toll Free: 1-800-498-1777