During four months of remedy hearing this spring she gave no hint of how she might rule.
Depending on the verdict, either the nine states that refused to go along with a deal between the Department of Justice and Microsoft reached last year, or the US government and the company itself, may appeal.
The remedy phase follows an appeals court decision 12 months ago that rejected a lower court ruling to break up the company but upheld a finding that Microsoft had illegally maintained its monopoly in the operating systems market.
The US government and half of the 18 states involved in the case settled soon after the appeals court decision. But nine other states - California, Connecticut, Florida, Kansas, Iowa, Massachusetts, Minnesota, Utah and West Virginia, as well as the District of Columbia - continued to push for tougher remedies.
Throughout the remedy hearing, which began on 18 March, Microsoft's lawyers attempted to show that the states' proposed remedies were too broad, exceeding the scope of liabilities that the Court of Appeals outlined last year and threatened fundamental damage not only to Microsoft, but also to the PC industry at large.
Perhaps the most controversial remedy proposed by the states would force Microsoft to sell an "unbound" version of Windows - one free from additional middleware programs such as a browser and media player - so that PC makers and end users could replace those programs with ones from competitors.
In a dramatic reaction to that proposal, Microsoft chairman and chief software architect Bill Gates testified in April that the company would be forced to pull Windows from the market if the remedy was accepted by Kollar-Kotelly
Removing such middleware from Windows would cripple other aspects of the operating system, Gates said in court. Because the proposed remedy says that the unbound version of Windows must be a functional equivalent to the full operating system, minus the removed middleware, Gates said there's no way Microsoft could satisfy the provision. That would force the company to stop selling Windows to avoid violating the remedy.