Two days of oral arguments in the U.S. antitrust case against Microsoft Corp. opened Monday with the lead lawyer for the software giant arguing that the company never foreclosed Netscape Communications Corp. from selling its browser in any part of the marketplace.

Richard Urowsky told the seven judge panel of the U.S. Court of Appeals for the District of Columbia that in 1998 Netscape enjoyed “unfettered access to consumers,” particularly over the Internet, which Urowsky said was used to download 60 million copies of Navigator out of a total 160 million copies sold that year.

“There is no evidence that there was any impediment to the distribution of Navigator in the marketplace,” Urowsky said. “Netscape was able to offer its software literally to every PC user worldwide.”

Urowsky also defended Microsoft’s decision to offer its browser together with Windows as a move that was not anticompetitive because it improved the product’s functionality and it did not impede the distribution of Navigator, he said. In addition, Urowsky said Microsoft’s deals with PC makers requiring Windows to start up uninterrupted was not anticompetitive, but rather an attempt to protect its copyright.

Urowsky argued first on the opening day of the company’s appeal of the U.S. District Court ruling against Microsoft that was handed down last year, including a proposed break-up remedy sought by the government. The appellate court opened the debate with the question of whether Microsoft’s actions constituted monopoly maintenance in violation of the U.S. Sherman Antitrust Act. The issue of “tying” the remedy and the statements, that have been made since the trial by the district court judge, will be covered Tuesday.

The government contends that Microsoft used its monopoly power to stifle competition, taking extraordinary steps and spending extraordinary amounts of money to prevent consumer access to Netscape’s product.

Jeffrey Minear, senior litigation counsel for the U.S. Department of Justice, argued that Microsoft’s internal documents revealed that it perceived Navigator as a threat to its dominance in the operating system market even though Navigator is not an operating system. The company reacted as it did because if Navigator became widely adopted, the tasks that it carried out as middleware could eventually overtake the tasks of the operating system, Minear argued.

The seven judges, all of whom posed questions during the morning session, showed a thorough understanding of not only the case, but also the relationship between software companies, PC makers and developers. At one point, at least two justices wondered whether the end result of the case might be that Microsoft’s monopoly would be replaced by another monopoly, perhaps Netscape combined with the technology of Sun Microsystems Inc., because ultimately consumers want to have just one choice.