Microsoft has been quietly slipping in WGA-like checks like KB971033 amongst the many updates in Windows Update. However, these initial anti-piracy checks are voluntary in basis. In fact, they even unchecked it by default. You can even "disable it" permanently by hiding the update. Even so, it was only a matter of time before Microsoft makes one of these anti-piracy updates mandatory. Normally, a mandatory anti-piracy check would be introduced when a service pack is scheduled to appear. You will need to submit to this anti-piracy check and pass it before you are allowed to install the service pack and gain access to future updates. We think that Microsoft has just introduced a mandatory anti-piracy update - KB976902. Link : ED#123 : Yet Another Anti-Piracy Update For Windows 7?