The offer is valid for customers buying a qualified pc i.e., a pc which is purchased within the promotional period with a valid Windows 7 OEM Certificate of Authenticity and product key. The promotional period goes on from June 2 till January 31, 2013. Users must register for the upgrade before February
Windows 8, the next upgrade to Microsoft’s Windows OS, is expected to be released around October 2012.
The offer is for customers (e.g. Home users, students, and enthusiasts) who purchase a qualified PC. A qualified PC is a new PC purchased during the promotional period with a valid Windows 7 OEM Certificate of Authenticity and product key for, and preinstalled with:
Windows 7 Home Basic;
Windows 7 Home Premium;
Windows 7 Professional; or
Windows 7 Ultimate.
The promotional price is limited to one upgrade offer per PC purchased, and a maximum limit of five upgrade offers per customer.
For complete offer details go to https://windowsupgradeoffer.com/en-US/Home/ProgramInfo