The program essentially frisks Windows users by requiring they verify the authenticity of their software in order to receive Windows XP add-ons, including anti-spyware software.

That means users of non-genuine Windows would no longer be able to get Windows updates, which also include Photo Story 3, Video Screensaver and 12 video tutorials on how to various tasks, including making a VPN connection using XP. Microsoft pegs the total value of these add-ons at about $450.

The program is designed to help Microsoft and its resellers reclaim revenue lost to piracy.

Earlier in the year there were rumors that the program would block pirated systems from accessing Windows security patches. But Microsoft said yesterday that all Windows users, including those of non-genuine programs, would still be able to download patches.

During the pilot there was speculation that Microsoft would block security updates for users running counterfeit copies of Windows, however that was inaccurate, said a Microsoft spokesperson. Microsoft wants to keep the Internet secure and it realizes that if it cuts off security updates for people running counterfeit Windows that’s going to essentially cause some security issues.

The new program does not affect enterprises with volume Windows licenses, which would be validated automatically and receive the add-on downloads, said the spokesperson.

SME and SOHO Windows users, however, would register on either the Microsoft Download Center, Windows Update or Microsoft Update site where they can download an ActiveX control that checks the authenticity of their software and stores a download key on their PC for future verification. Previously, users had to enter their 25- digital product key to validate their software.

Users of a non-genuine Windows system can send in the pirated CD and proof of purchase, and fill out a form in exchange for a legitimate copy at no charge. Or, if they don’t have the original CD, buy a new copy of the software at a discounted price: $99 for Windows XP Home (which retails for $199) or $149 for XP Professional ($299 retail).

Microsoft declined to comment on whether a similar program would also be launched for the company’s upcoming Vista operating system, previously codenamed Longhorn, which is slated to be released in the second half of 2006.

Microsoft launched a pilot of its Genuine Advantage program in the US last fall and in February expanded it to more than 20 countries. As of July 4, about 82 million Windows users viewed an opt-in page to the pilot program and of those 58%, or 47 million, joined, according to Microsoft.

Microsoft said it would not collect any information about a user during the validation process that can be used by the company to identify or contact the user.