Lawyers in the "Windows Vista Capable" class-action lawsuit against Microsoft have asked a federal judge to force the company to use its Windows Update service to notify potential class members, court documents filed Thursday revealed.

In a motion submitted to US District Judge Marsha Pechman, lawyers for the plaintiffs laid out a notification plan that would include print ads in publications such as USA Today, banner ads on sites including Yahoo.com and MSN, and a message that would be delivered to Windows users by Microsoft's automatic update service.

Noting that Microsoft has repeatedly said it cannot identify the people who bought PCs under its Vista Capable marketing campaign in 2006 and early 2007, the plaintiffs' attorneys pitched Pechman on the idea of using Windows Update to reach them. "Although Microsoft cannot identify class members, it can communicate to them through its Windows Update program," the motion filed Thursday said.

Windows Update is the mechanism best known for delivering security patches to Windows users on the second Tuesday of each month. However, the service also is used by Microsoft to push non-security updates, and in some cases has been used to patch third-party products.

It has not, however, been used for legal messages such as the one proposed by the plaintiffs' lawyers.

The attorneys argued that Windows Update would be a "low-cost" and "efficient" way to reach potential class members. One of the plaintiffs' expert witnesses, independent IT consultant Ronald Aelpin, said that the Windows Update notification would "cost little more than the amount necessary to write, test, and implement the small piece of software code necessary to provide the notice."

Tom Horn, a second expert used by the plaintiffs' lawyers, was even more concise, estimating that it would take Microsoft just "one to two man hours to complete the program, address quality assurance issues, tag and upload the Update as ready for distribution."

Supporting documents also filed yesterday with Pechman spelled out the exact wording the notice would use: "Court Ordered Notice Regarding Windows Vista Capable Class Action. If you purchased a computer certified as 'Windows Vista Capable' and not also bearing the 'Premium Ready' designation, your rights may be affected by a class action lawsuit. Click here for more detailed information."

A link in the notice would lead users to a specially-crafted site with more information on the case.