The world's richest man, Microsoft founder and chairman Bill Gates, Monday appeared in a Washington court room giving his opinion of proposed remedies to the U.S. government's anti-trust case against his company.

Mr. Gates told a federal judge that sanctions sought by the nine U.S. states accusing Microsoft of monopolistic practices would cripple his company.

He said the proposal that Microsoft modify its Windows computer operating system so that rivals software could be used on it is unworkable.

Such action, he said, would make Windows unstable and set the operating system back ten years. He said the proposal that Microsoft disclose its Window code would permit competitors to clone the operating system, which ninety percent of the world's personal computers use.

Monday Mr. Gates made his first courtroom appearance in the four-year long antitrust battle. "I hope that my testimony helps the court to resolve the issues in this case," he said. "That would be best for consumers and for the industry. And that is why I am here."

The Justice Department brought the landmark anti-trust case against Microsoft during the Clinton administration. Once Bush assumed the presidency, the Justice Department backed away from demanding that the company be split up and agreed to settle the case last November. Nine dissenting states oppose the settlement and want harsher action against the company. The hearings on sanctions are expected to continue through May.

Mr. Gates said the states' plan would devalue Microsoft and force it to withdraw Windows from the market. The states say Windows could be modified and that in modular form, it could run on rival operating systems like Linux and Unix. Such a change, they argue, would boost competition and encourage innovation.