Even as Microsoft's product groups focus on Windows 7 and beyond, its lawyers are still battling disgruntled PC users over the way the company distributed an anti-piracy tool for Windows XP -- the version of the operating system that debuted nearly eight years ago.

The case, more than 3 years old, is still relevant for its focus on what Microsoft should -- and shouldn't -- be allowed to pipe to users through Automatic Update and other mechanisms for patching Windows PCs. The company has separately raised eyebrows by distributing new versions of Internet Explorer through the same channels.

The plaintiffs allege that Microsoft improperly distributed the Windows Genuine Advantage tool, without proper consent from users, in a manner normally reserved for "high priority" security updates. WGA, as it's known, tests to see if a copy of Windows is valid and delivers warnings if it doesn't pass. Microsoft's Automatic Update system lets users opt in to receive fixes and patches for the operating system.

Microsoft disputes the plaintiffs' longstanding contention that the distribution of WGA through Automatic Update amounted to the installation of unauthorized spyware on users' machines.

The dispute has been slowly proceeding toward a possible trial. The big question is whether it will be certified as a class action, potentially opening up the case to millions of additional PC users. Three weeks ago, on Sept. 22, Microsoft filed a formal opposition (PDF, 52 pages) to the class certification bid -- saying the company acted properly in distributing WGA and describing the plaintiffs' claims as a "fictional thesis."

"In fact, Microsoft provided a wide array of information about WGA Validation, and proposed class members read information and gave their consent through many different affirmative acts before choosing to install WGA Validation," the company says in its response.

Microsoft in June won a key battle when U.S. District Court Judge Richard Jones ruled (PDF, 9 pages) that its distribution of WGA for XP didn't violate the terms of the end user license agreement (EULA) for the operating system. That ruling was notable for its finding that WGA's collection of a user's IP address didn't violate the EULA's promise not to transmit "personally identifiable information" without the user's consent.

"In order for 'personally identifiable information” to be personally identifiable, it must identify a person. But an IP address identifies a computer, and can do that only after matching the IP address to a list of a particular Internet service provider’s subscribers," the judge wrote. "Thus, because an IP address is not personally identifiable, Microsoft did not breach the EULA when it collected IP addresses."

One of the plaintiffs, Charles Ellis, recently appealed that ruling on the breach-of-contract claim to the U.S. Court of Appeals for the 9th Circuit. Documents related to the appeal say the remaining plaintiffs are continuing to pursue the case separately, in federal court in Seattle, on allegations of trespass, unjust enrichment and Washington Consumer Protection Act violations.

Microsoft has made a series of changes in Windows Genuine Advantage in response to repeated criticism. For Windows 7, the company has rebranded the anti-piracy tools "Windows Activation Technologies."