Right now, the case is scheduled to go to trial on April 13 with the six named plaintiffs.

On Feb. 26, plaintiffs' lawyers asked Pechman to delay the trial to allow time to consider their request for certification of a narrower class of plaintiffs and, if granted, to notify potential members of the narrower class.

Pechman rejected the original class because the plaintiffs failed to offer solid evidence of the "price-inflation theory" -- the idea that the Vista Capable marketing program resulted in higher prices paid by the entire class of people who purchased PCs marked with a "Capable" logo. "Absent evidence of class-wide price inflation, plaintiffs cannot demonstrate that common questions predominate over individual considerations," Pechman wrote in her decertification ruling.

The two new narrower classes the plaintiffs are seeking (outlined in this 5-page PDF motion for continuance) would consist of purchasers in Microsoft's Express Upgrade Guarantee program who requested an upgrade to Vista and purchasers of Vista Capable PCs that lacked support for the Windows Display Driver Model (WDDM), which was necessary to run certain graphics features of Vista.

Plaintiffs' lawyers wrote that the analysis of these classes -- particularly their proposed proof of proximate cause (the idea that a defendant's act caused consequences reasonably related to that act) -- is "materially different" from the issues in the decertified class. For the Express Upgrade class, the members' "affirmative participation" in the program and "request for the Vista upgrade" can establish proximate cause. The second proposed class of Vista Capable PC purchasers would "have a pure omission claim against Microsoft," assuming the plaintiffs argument that a PC unable to support WDDM can't be fairly called "Vista Capable" holds up in court.

The attorneys note that even though Pechman decertified the class, she "ruled that plaintiffs had nevertheless presented issues for trial warranting denial of Microsoft's summary judgment motion."

Updated, 6:33 p.m.: After hearing oral arguments from lawyers for both sides this afternoon, Pechman said they should look for a ruling from her early next week. But the judge also indicated she doesn't think the case will proceed to trial with the six individually named plaintiffs as scheduled April 13. Pechman said she expects Microsoft to appeal her decision if she certifies the new classes and the plaintiffs to appeal if she does not. In either case, asking the 9th Circuit Court of Appeals to review the decision would likely put the scheduled jury trial on hold.