In a written deposition (PDF) to court Microsoft chief executive Steve Ballmer has denied all knowledge of the Vista Capable marketing programme that resulted in a class-action suit against the company.

The prosecution had been hoping to get Ballmer on the stand to justify the initiative, but this now seems unlikely in light of his written statement.

Ballmer stated that he was kept informed of the campaign by Jim Allchin, Microsoft's retired co-president for platforms, products and services, and Will Poole, former senior vice president for Windows client business, who has since left the company.

"I was not involved in establishing the requirements computers must satisfy to qualify for the Windows Vista Capable programme," the deposition reads.

"I was not involved in formulating any market strategy or any public messaging surrounding the Windows Vista Capable programme.

"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 programme."

The court case was brought by angry consumers who found that laptops they had bought were capable of running only the most basic form of the operating system, Vista Home Basic.

Retailers also expressed concerns about the programme, which was intended to shore up pre-Christmas sales of computers after Vista's launch was delayed until the New Year.

It also emerged that senior executives within Microsoft were unhappy with the situation. Allchin wrote in an email: "We really botched this. You guys have to do a better job with our customers."