How does WGA for Windows Vista® work?
WGA for Windows Vista® enables Microsoft® to help differentiate the genuine Windows Vista® user experience by reserving key product features, including Windows® Aero™ Windows Defender, and Windows® ReadyBoost™ for customers running a genuine properly-licensed copy of Windows Vista®. Systems running a non-genuine copy of Windows Vista will be notified, and the lower right portion of their screen will permanently display a message that reads, “This copy of Windows® is not genuine.” In addition, a user may be asked to reactivate within 30 days if it is determined that their product key has been blocked by Microsoft® or their licensing files have been tampered with. Failure to reactivate within the 30-day grace period may result in the system being placed into a reduced functionality mode.