The European Commission will discuss its draft negative antitrust ruling against Microsoft with national competition regulators from the 15 EU countries on 15 March.
The commission believes Microsoft is guilty of abusing the dominant position of its Windows operating system - a view likely to be supported by the national regulators.
A second meeting will be convened within a week to discuss what remedies to impose on Microsoft to prevent it from continuing to break EU antitrust laws. The second gathering of the so-called advisory committee will also discuss how much to fine the company.
"I expect more debate among the national regulators and the commission at the second meeting," said a diplomat close to one national regulator, who preferred not to be named.
A final ruling by the commission normally follows a few days after the second committee meeting, which is likely to be 23 or 24 March.
Microsoft has said it still hoped to settle with the commission before it makes its ruling.
The commission, which decides on the timing of these meetings, declined to comment.
By tying in its Media Player music and video playing software into Windows, Microsoft has put rival players at an unfair competitive disadvantage, the commission found.
It also found that, by withholding crucial information about how Windows works, the company has also disadvantaged competitors in the market for server software that runs networks of PCs. Microsoft's own server software works better with Windows on PCs than rivals' server systems.
Mario Monti, the European Commissioner for competition, wants Microsoft to propose within a few months of the ruling what computer code inside Windows that should be revealed to create a level-playing field in the server software market.
The commission wants Microsoft to sell two versions of Windows: one with Media Player stripped out and sold separately, and the other with the software included.
Paul Meller writes for IDG News Service