Microsoft has reached a preliminary settlement in a class-action lawsuit in Minnesota, which alleged, as usual, that the company had abused its Windows monopoly to overcharge customers in the state for its software.

As a result of the settlement, the trial, which began 15 March, has been concluded and the jury has been discharged, the Hennepin County District Court website states. The terms of the settlement will remain confidential until finalised in early July.

The Minnesota case is one of several class-action lawsuits brought against Microsoft on behalf of consumers in the wake of the US government's antitrust case that the vendor had been unable to settle or get dismissed.

Cases in Arizona, New Mexico and Iowa could still be headed for trial, and the Nebraska Supreme Court last month reversed earlier rulings that blocked a consumer class action case in that state. In New York, Ohio, Wisconsin and Michigan courts have initially declined to certify classes of consumers, but plaintiffs are appealing those decisions, Microsoft spokesman Jim Desler said.

Cases in Vermont and Massachusetts are also still active, but not as close to going to trial as the Arizona, New Mexico and Iowa cases because classes of consumers have not yet been certified, according to Desler.

In settlements reached with lawyers representing consumers in states including California, Tennessee, North Dakota, South Dakota and Kansas, Microsoft agreed to make vouchers available to customers who bought Microsoft software during a specific time period. The vouchers can be used to buy computer software or hardware.

In earlier statements, Microsoft denied it did anything wrong in Minnesota. "We remain confident in our case, and that did not change at all during trial," Microsoft spokeswoman Stacy Drake said on Monday. Microsoft is not admitting guilt as part of the Minnesota settlement, she said. Settlement negotiations had continued off and on during the trial and bore fruit on Friday, Drake said. "We have said from the beginning that we would be open to looking at reasonable ways to settle this case," she said.

Lawyers for the Minnesota plaintiffs were seeking damages of as much as $505 million, accusing Microsoft of having overcharged software buyers in the state between 1994 and 2001, said Rick Hagstrom, laywer for the plaintiffs. The damages amount could have been trebled under Minnesota law, he said. "We were putting on our evidence and we were happy with how the case was proceeding," Hagstrom said.

Opening arguments in the Minnesota case began 15 March. The court had allotted three months for the trial. As part of its defense, Microsoft had said it may have called Bill Gates and Steve Ballmer to testify. The settlement was reached before Microsoft even started its defense.

Trial exhibits in the Minnesota case will be available on the court's website until Monday, 26 April and offer an insight into Microsoft's business back to the early days of the company when it was peddling DOS.

Microsoft has been busy clearing up lawsuits filed against it. Earlier this month it agreed to pay $1.6 billion to Sun Microsystems to settle a private anti-trust suit and resolve patent issues, and $440 million to InterTrust Technologies to end a dispute over digital rights management patents.

"Microsoft is making a real drive to take care of some of these cases and that could free up cash to be used for other purposes," said Matt Rosoff, an analyst at Directions on Microsoft, referring to Microsoft's $52.8 billion in cash and short-term investments. The company had said it was holding onto that money partly because of legal uncertainties.

Among the other cases that Microsoft still has to resolve is a European anti-trust case. The European Commission last month fined Microsoft €497 million (£330m) for anti-competitive behavior. Microsoft is appealing the decision.