PC buyers suing Microsoft over its "Windows Vista Capable" marketing campaign haven't yet shown that the company deceived them by giving that designation to computers that couldn't run the operating system's fancy graphics.

That was the ruling late yesterday from U.S. District Judge Marsha Pechman (PDF, 7 pages), denying a longstanding motion by the plaintiffs for partial summary judgment. The decision leaves the issue to be decided in an upcoming trial. Pechman's ruling came despite a series of emails in which Microsoft executives expressed concern about lowering the standards for the "Vista Capable" designation.

"I believe we are going to be misleading customers with the Capable program," then-Windows chief Jim Allchin said in one of those messages. "OEMs (computer makers) will say a machine is Capable and customers will believe that it will run all the core Vista features. The fact that aero won't be there EVER for many of these machines is misleading to customers."

Email exchanges suggested that Microsoft lowered the standards at the behest of Intel, which still needed to sell an older chipset that wouldn't have met the previous requirements for the Vista Capable designation.

In her ruling, Pechman reiterated her previous finding that the emails “raise a serious question about whether customers were likely to be deceived by the WVC campaign." However, she added, "these communications do not establish that Microsoft’s actions, as a matter of law, had a capacity to deceive a substantial portion of the public. A trier of fact must analyze both internal discussions and public disclosure to determine whether the Vista Capable campaign had a capacity to deceive."

The public disclosure in this case included marketing materials and other efforts by Microsoft to explain that some "Windows Vista Capable" machines wouldn't run the advanced Aero graphics and other signature features of the operating system.

Separately, Pechman recently removed the class-action status from the case, but the plaintiffs have asked her to reinstate it for a narrower group of PC buyers. A hearing on that issue is scheduled for next week.