How is the Windows Vista non-genuine experience different from Windows XP?
For genuine customers of Windows Vista, Microsoft is providing Windows Aero and Windows ReadyBoost features as well as removing those classes of spyware identified by Windows Defender. Genuine customers will also have access to all classes of updates and new feature upgrades. If a user tries to run a non-genuine copy, they may be required to reactivate and could lose access to Windows Aero, Windows ReadyBoost and the full functionality of Windows Defender. On systems running a non-genuine copy of Windows Vista, the lower-right portion of the screen will permanently display a message that reads “This copy of Windows is not genuine.” Systems that do not activate properly may fall into a reduced functionality mode after a 30-day grace period.