"What did Mr. Otellini say? Why had the issues escalated so far? How did Mr. Ballmer react?" the motion asked. "The only way for plaintiffs to know the answers to these and other questions is to ask the participants on the call."

Microsoft has asked U.S. District Court Judge Marsha Pechman to block the plaintiffs' attempt to . In an October filing, Ballmer claimed, "I do not have any unique knowledge of, nor did I have any unique involvement in any decisions regarding the Windows Vista Capable program."

The plaintiffs' lawyers feel otherwise. "Mr. Ballmer's connection to the Vista Capable program is not limited to a single -- albeit significant -- telephone call with Intel's CEO," their motion read. "Mr. Ballmer was an active participant before, during and after the program."

According to the motion, other meetings were scheduled between Ballmer and major Microsoft partners. Executives at the Best Buy retail chain, for example, asked that their concerns over the Express Upgrade program -- an offer that gave PC buyers free or discounted upgrades to Vista -- be bumped up "to a senior level." A meeting was later scheduled between Best Buy's vice president Ron Boire and Ballmer.

The plaintiffs' lawyers said that they had found no record in the documents Microsoft provided of Ballmer's response, if any, to the complaint e-mailed by HP's CEO. "Presumably the two CEOs had a telephone conversation," the motion speculated.