Key dates in the antitrust case against Microsoft Corp.:

1975: Microsoft founded by Paul Allen and Bill Gates.

July 1994: Microsoft, in a consent decree, agrees to change contracts with PC makers and eliminate some restrictions on other software makers, ending a Justice Department investigation.

August 1995: Microsoft launches Windows 95 operating system.

September 1997: Microsoft launches Internet Explorer 4.0 in stepped-up challenge to Netscape Communications Corp.

1998

May: Justice Department and 20 state attorneys general sue Microsoft, charging it illegally thwarted competition to protect and extend its monopoly on software. One state later drops from the suit.

October: Justice Department sues Microsoft, alleging it violated the 1994 consent decree by forcing computer makers to sell its Internet browser as a condition of selling its popular Windows software.

1999

Aug. 27: Government lawyers question Gates for 30 hours over three days in a videotaped deposition. Excerpts are shown in the courtroom during the trial.

Oct. 19: The antitrust trial begins.

Nov. 5: U.S. District Judge Thomas Penfield Jackson, in preliminary findings, declares Microsoft a monopoly. He rules that the company's actions are "stifling innovation" and hurting consumers.

Nov. 19: Jackson appoints Richard Posner, chief judge for the 7th U.S. Circuit Court of Appeals in Chicago, as a mediator to oversee voluntary settlement talks between the government and Microsoft.

2000

Jan. 18: Microsoft, in its first formal response to the court's ruling, says its Windows software doesn't represent a monopoly because the company doesn't control the price or availability of software to run the world's personal computers.

Feb. 22: Jackson hears final round of arguments, rejects key legal defense for Microsoft.

April 1: Talks between federal government and Microsoft break down and Posner says he is ending his mediation effort.

April 3: Jackson finds that Microsoft violated the Sherman Antitrust Act, "maintained its monopoly power by anticompetitive means" and attempted to monopolize the Web browser market. The judge also rules that Microsoft violated another section of the law by "unlawfully tying its Web browser to its operating system" and could be sued under state anti-competition laws.

April 28: The Justice Department and 17 state attorneys general ask Jackson to break the company into two parts: one company to develop and market the Windows operating system and the other to develop Microsoft's other software and Internet holdings, including the Microsoft Office suite of programs.

May 10: Microsoft asks Jackson to throw out the Justice Department's plan, saying the penalty would far exceed the antitrust violations the judge found the company to have committed.

June 7: Jackson orders the breakup of Microsoft into two companies, declaring the software giant had "proved untrustworthy in the past."

Sept. 26: Supreme Court refuses to hear Microsoft's appeal of Jackson's decision, sending the case instead to a federal appeals court in the District of Columbia.

2001

January: Government and Microsoft filed briefs to the federal appeals court. Microsoft says Jackson's many comments to journalists show his bias against the company.

Feb. 26-27: Appeals court hears oral arguments. Judges lambaste Jackson for extrajudicial comments.

June 28: Appeals court throws out breakup order, citing Jackson's comments.

Aug. 7: Microsoft asks Supreme Court to take up case.

Aug. 24: U.S. District Judge Colleen Kollar-Kotelly picked at random to take up Microsoft case.

Sept. 6: Justice Department announces that it will no longer seek a breakup of Microsoft.

Sept. 28: Citing the Sept. 11 terror attacks, Kollar-Kotelly tells Microsoft and the government to negotiate around the clock to settle the case by Nov. 2.

Oct. 9: Supreme Court says it will not hear Microsoft appeal.

Oct. 13: Judge names professional mediator, Eric D. Green, a professor at Boston University's law school, to oversee settlement talks.

Oct. 25: Microsoft releases Windows XP, its newest operating system. Separately, the 18 states and the District of Columbia suing Microsoft hire their own lawyer.

Oct. 31: Microsoft, Justice Department reach tentative deal to settle antitrust case.

Nov. 6: Nine states announce they have agreed to join the Justice Department's settlement of antitrust charges against Microsoft.

Dec. 7: The other nine states and the District of Columbia, which declined to join the federal settlement, call for stricter sanctions against Microsoft. They want the company to put Internet Explorer into the public domain, translate its Office productivity suite to other operating systems, and let computer makers remove some Windows features.

2002

Jan. 23: AOL Time Warner sues Microsoft, seeking damages for Microsoft's illegal acts against its Netscape browser company.

Jan. 28: Public comment period ends in settlement. About 30,000 people send messages about the deal, and criticisms outnumber statements of support 2-1.

Mar. 6: Justice Department and Microsoft defend their settlement. Six parties, including SBC Communications and several trade groups, lodge their protests in court.

Mar. 8: Sun Microsystems files private antitrust suit against Microsoft, alleging "extensive" anticompetitive practices.

Mar. 18: States begin remedy hearings before Kollar-Kotelly.

Apr. 22: Gates testifies in defense of his company, the first time the chairman takes the stand during the entire four-year antitrust battle.

Jun. 19: Remedy hearings end.

August: Microsoft unveils several business and product changes to comply with the settlement, including giving users the ability to hide Microsoft programs like its Web browser and only see competing products.

Friday: Kollar-Kotelly approves most provisions of antitrust settlement.