Microsoft Corp. decided to take its antitrust care directly to the Supreme Court on Tuesday, asking it to overturn a previous court ruling that the software giant is an illegal monopoly.

Microsoft sent the petition to the high court two days before the case was to be sent to a new judge to decide what penalty the Redmond, Wash., firm should face.

Simultaneously, Microsoft asked the appeals court that currently has the case to hold off any action until the Supreme Court decides whether to take the case, company spokesman Vivek Varma said.

A federal appeals court in June threw out a U.S. District Court judge's order breaking the company in two, saying a new lower court judge should hold hearings to fashion a punishment, which could still include a breakup.

In its Supreme Court appeal, Microsoft said District Judge Thomas Penfield Jackson's entire ruling should be thrown out because the appeals court found that he violated the judicial ethics code.

"On that basis, Microsoft argues that the district judge should have been disqualified from any further role in the case as of the time the earliest violation occurred," Microsoft told the court. The appeals court strongly condemned Jackson's actions, but said that nevertheless Microsoft still acted as an illegal monopoly."

Through a spokeswoman, Jackson declined to comment Tuesday.

Last week's Ruling Could Imperil Windows XP

Last week, the appeals court turned down Microsoft's request to reconsider one of the court's key findings, that the software maker illegally combined its Windows operating system with its Web browser. That ruling could jeopardize Microsoft's upcoming operating system, Windows XP, because it includes many more programs that had previously been sold separately.

This is the second time the nation's highest court will consider whether to take up Microsoft's antitrust case. After the company appealed Jackson's ruling last year, the Justice Department wanted to fast-track the case to the Supreme Court, bypassing the appeals court. Microsoft objected, and the justices denied the government request in September.

Microsoft thought that it would have an easier time with the appeals court, since that court had ruled for the company in the past. The Justice Department wanted to go straight to the Supreme Court for the same reason. Now, their roles are reversed.

Microsoft Playing With Time

Legal experts said they doubted the Supreme Court would take the 4-year-old case, and that Microsoft is playing for time.

"The Supreme Court is not going to reverse the Court of Appeals, Microsoft is not going to walk free, so it's a delaying tactic," University of Baltimore law professor Bob Lande said. "They have no realistic chance of getting this overturned."

Lande said Microsoft wants to keep litigating while it finishes up Windows XP, which will be sent to computer manufacturers in August and to stores in October.

Both Congress and several state attorneys general have asked Microsoft to change Windows XP, saying that it would repeat many of the same business practices already found to be illegal and would force consumers to use more Microsoft products.

Microsoft maintains that it is only providing the features consumers want, and that its customers will benefit from Windows XP if they choose to buy it.

--The Associated Press contributed to this report.