Yet the ruling does not mean Microsoft is untouched. A federal appeals court last year found that Microsoft was a monopolist in the personal computer operating system market, and that it had repeatedly abused its monopoly power to thwart competition and stymie innovation. That means Microsoft is a court-decreed monopoly that is in the process of becoming regulated.

But based on Judge Kollar-Kotelly's ruling, that regulation will be done with a light touch. "It shows a great reluctance to go down the regulatory path," said Robert E. Hall, an economist at Stanford, who has done consulting work for Microsoft.

Her reluctance, Judge Kollar-Kotelly noted, was grounded in the appeals court's ruling of June 2001. It upheld the monopoly ruling of the district court and several of its findings against Microsoft, but it also narrowed the scope of Microsoft's liability and brushed aside the lower court's order to break the company in two.

....Last month, in the middle of a severe slump in the technology industry, Microsoft reported that its quarterly profit rose 40 percent and its sales increased 26 percent. Part of the surge was attributable to a new pricing plan that raised charges for many purchasers and brought a chorus of protests from corporate customers. But nearly all of them paid up and went along.

"Microsoft may be a little bit more restrained and a little bit less aggressive because of the antitrust case," said David B. Yoffie, a professor at the Harvard Business School. "But not much. Microsoft's market power has been unimpeded by the case."

Still, as some analysts note, the company's corporate culture does seem to have been altered by the long litigation.

It seems to have been, they say, a hard-learned lesson in humility. "Internally, within Microsoft, I think the company is very different," said Michael Cusumano, a professor the Massachusetts Institute of Technology's Sloan School of Business. "I think they are less aggressive with customers and partners than they were, and more respectful of the law."

But, Mr. Cusumano said, "Not much has changed in the marketplace."

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The U.S. Justice Department applauded the ruling, saying the settlement would both address Microsoft's unlawful conduct and restore competitive conditions in the software industry.

Attorney General John Ashcroft said the department was "strongly committed" to ensuring that Microsoft complies with the settlement and will continue to closely monitor the company's implementation of its terms.

An appeals court ruling in June 2001 upheld trial court findings that Microsoft had illegally maintained its Windows operating system monopoly, but rejected breaking the company in two. The case was then transferred to Kollar-Kotelly to determine the appropriate remedies in the case.

"Microsoft lost every battle and they won the war," said Shane Greenstein, technology business professor at the Kellogg Graduate School of Management at Northwestern University. "The lesson everyone learned here is just stay out of Microsoft's way."