Downloading Windows 7 for free is primarily possible for students or faculty at universities with a site license that permits distribution for educational purposes. Microsoft does not support requests for illegal download sites. Upgrading from Windows Vista to Windows 7 may be done at no cost if users stay within the same architecture (32-bit or 64-bit), but this typically requires a purchase of an upgrade edition. The upgrade process involves obtaining a 25-character product key, which is provided when Windows 7 is purchased. Options for purchasing include the Windows 7 Home Premium Upgrade for those currently using Vista or XP, and a full version for those not using these operating systems. The upgrade family pack is available for around $150, offering multiple upgrade licenses.