From Gerrit Grunwald
An improved WGA version is to be integrated into Service Pack 1 for Windows Vista. With the help of system dialogs and the chance to purchase a legal license, the user is made aware that an unlicensed version of Windows is installed on the computer. This is primarily intended to protect unsuspecting computer users.
Once an illegal copy has been detected, no further updates can be installed. No further details are known at present.
This dialog box informs users about an unlicensed Windows version.