This question has come up a number of times in the forums so I thought it would be best to address it separately. The question of upgrading any Home editions to Professional editions is a legal licensing one. The Home editions and Professional / Business / Enterprise are two different product lines. In order to upgrade to a Professional edition, you must already have a legal license for another professional edition. The Windows 7 product page states: "This is an upgrade product. To install this operating system, you must have a licensed installation of one of the following operating systems on the device where you are installing the upgrade: Windows Vista Enterprise, Business, or Ultimate; Windows XP Professional or Tablet PC; Windows 2000 Professional; Windows NT Workstation 4.0; or Windows 98. You cannot upgrade from the Home editions of Windows XP or Windows Vista."
At this time, there is no legal upgrade path from Home editions to the professional products that Microsoft has made available through TechSoup Stock. Your best options are to either upgrade to Windows 7 Home, or find a full licensed version of Windows 7 Professional through a Charity Reseller.
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