Judge Colleen Kollar-Kotelly was named Friday to decide how Microsoft should be punished for violating federal antitrust laws.
Kollar-Kotelly, an appointee of President Clinton, takes over the case from U.S. District Judge Thomas Penfield Jackson, who had ordered Microsoft split.
The random selection of Kollar-Kotelly follows the U.S. Court of Appeals for the District of Columbia's decision early Friday to send Microsoft Corp.'s four-year antitrust case back to a lower court.
Kollar-Kotelly will now have the task of holding hearings on what remedies should be imposed to prevent any further abuse of Microsoft's monopoly in personal computer operating systems. She must also decide whether Microsoft violated antitrust laws by tying its Internet Explorer browser into the Windows operating system.
The penalty could require simple changes in Microsoft conduct or a breakup of the Redmond, Wash., firm. Judge Jackson ordered the company be split in two, but that portion of his ruling was overturned by the appeals court in June.
The appeals court last week rejected Microsoft's request to delay the company's antitrust case until the Supreme Court decides whether to take the case. Microsoft had also said that if the appeals court didn't put the case on hold, it would put the public's faith in the judicial system in jeopardy.
The appeals court unanimously disagreed.
"Microsoft has failed to demonstrate any substantial harm that would result from the reactivation of proceedings in the district court," the appeals court ruled.
"It appears that Microsoft has misconstrued our opinion, particularly with respect to what would have been required to justify vacating the district court's findings of fact and conclusions of law," the court wrote.
The Supreme Court may still decide whether to hear Microsoft's appeal, but a decision is not expected before October.
Reuters and the Associated Press contributed to this report.