Attempting to conclude a lawsuit that has brought to light reams of internal Microsoft e-mails, the company today argued that the plaintiffs in the Windows Vista Capable case haven't proven their core legal arguments. In motions filed this afternoon in U.S. District Court in Seattle, Microsoft asked the judge to decertify the class action (PDF, 31 pages) and grant it summary judgment (PDF, 30 pages).

Here's an extended excerpt from the company's summary judgment motion.

"First, the evidence refutes Plaintiffs claim that Windows Vista Home Basic cannot fairly be called Windows Vista. Windows Vista Home Basic has nearly all of the same computer code as the rest of the Windows Vista family, and Microsoft developed it as an integral part of developing Windows Vista. Further, Microsoft never publicly defined Windows Vista in a way that would exclude Windows Vista Home Basic. Instead, it consistently marketed Windows Vista Home Basic as an edition of Windows Vista (as it does today), and it provided accurate information on the features available in that edition. The fact that Windows Vista Home Basic lacks some features available in premium editions of Windows Vista (as Microsoft always disclosed) shows only that Microsoft properly markets Windows Vista Home Basic as a distinct budget edition; it has no bearing on this motion.

"Second, Plaintiffs have no evidence that the Windows Vista Capable program (WVC program) caused an artificial increase in the demand for or prices of Windows Vista Capable PCs (WVC PCs) that were not Premium Ready. Plaintiffs expert, Dr. Keith Leffler, cannot quantify any increase in demand or PC prices. He did not even try to assess factors that influence PC demand such as promotions, discounts, rebates, and product bundling, or the undeniably accurate aspects of the WVC program that appeared on Web sites, in stores and in the press nor did he examine PC prices at all. In fact, Dr. Leffler admits that he cannot develop the price inflation theory in a credible way.

"Third, Plaintiffs cannot prove that Microsoft unjustly retained any benefit conferred by the class based on the sale of PCs by third parties."

The lawsuit alleges that Microsoft's marketing program wrongly gave the "Vista Capable" label to computers that couldn't run the operating system's signature features, such as the Aero Glass interface.

Documents turned over in the case show Microsoft executives opposing a decision to lower the standards for the Vista Capable designation, with former Windows chief Jim Allchin saying in one e-mail that he believed the Vista Capable program would mislead consumers.