The only thing CEO Steve Ballmer knew about Microsoft's Windows Vista Capable marketing campaign was what he was told by subordinates, and he should not have to testify in the class-action lawsuit that accuses the firm of deceiving customers, the company said Friday.

In a motion filed Friday, Microsoft asked US District Court Judge Marsha Pechman to block the move by plaintiffs' attorneys to depose Ballmer later this month. Lawyers for the plaintiffs want Ballmer on record in the case, which charges Microsoft duped consumers when it touted then-current PCs as "Vista Capable" in the months leading up to the late-2006 launch of the new operating system.

A Microsoft spokesman said the opposing lawyers were grandstanding. "This unnecessary request to depose Steve Ballmer is part of an effort by class action lawyers to generate media interest in topics that fall outside the narrow theory the court allowed them to pursue in this lawsuit in February," said company spokesman David Bowermaster.

In a declaration submitted to Pechman, Stephen Rummage, an attorney with Davis Wright Tremaine, which is representing Microsoft in the case, said that he told plaintiffs' attorneys that Ballmer would not be available for a deposition before the Nov. 14 cut-off. "After briefly describing our understanding of the law, I told [plaintiffs' attorneys] that Mr. Ballmer had no unique or superior personal knowledge of any disputed facts, asked them to explain why they thought Mr. Ballmer's testimony was necessary, and requested that Plaintiffs rethink their request to depose Mr. Ballmer," Rummage told the judge.

Ballmer echoed that in his own declaration, also filed Friday. "I was not involved in any of the operational decisions about the Windows Vista Capable program," he said. "I was not involved in establishing the requirements computers must satisfy to qualify for the Windows Vista Capable program. I was not involved in formulating any marketing strategy or any public messaging surrounding the Windows Vista Capable program.

"To the best of my recollection, I do not have any unique knowledge of nor did I have any unique involvement in any decisions regarding the Windows Vista Capable program," Ballmer added.

All he knew about Vista Capable was what subordinates, particularly Jim Allchin, the Windows development chief who took Vista to market before retiring in early 2007, and Will Poole, the former senior vice president responsible for the client version of Windows, told him. Ballmer admitted having had only "brief discussions about technical requirements and timing" for the marketing effort with high-level executives at partners such as Intel.

Microsoft's Bowermaster declined to comment late Friday when asked why Ballmer was not more involved in the Vista Capable marketing campaign. At the time of Vista's debut in November 2006, Microsoft touted the unveiling as its "biggest ever in the history of Microsoft product launches."

The plaintiffs' attorneys also asked for testimony from other current and former Microsoft executives , including Allchin, Poole and Rajesh Srinivasan, a product manager in the Windows group at the time of Vista's launch. Lawyers will take their depositions starting Monday.

The lawsuit, which began in 2007 and was granted class-action status in February 2008, claims that Microsoft ran a "bait and switch" by touting slower, less-expensive PCs as able to run Vista when they would handle only Vista Home Basic, the least expensive version of the OS. The suit argues that Home Basic is not representative of the Vista that was heavily marketed to consumers.

The case is perhaps best known for the hundreds of internal Microsoft e-mails made public earlier this year, but it resurfaced Friday after lawyers for the plaintiffs asked Pechman to force Microsoft to use Windows Update to notify users that they may qualify for inclusion in the case.