Microsoft's anti-piracy validation service, Windows Genuine Advantage or WGA, has gone from an opt-out service to a required service.

Microsoft has made this process a carrot-and-stick situation with tangible benefits for having a genuine copy of Windows.

After downloading the required ActiveX control, your version of Windows is validated for 90 days.

After 90 days, you would require revalidation as Microsoft may have received new product keys that are out there in the wild.

All in all, a pretty customer-friendly process.