WASHINGTON (Reuters) - A U.S. federal judge ruled Friday that Microsoft Corp. wields monopoly power in personal computer operating systems, a major setback for the world's largest software company in one of the biggest antitrust cases of the century. In 207-pages on the facts established at trial, District Judge Thomas Penfield Jackson said Microsoft's actions had done consumers harm and the company had used its power to punish competing firms. The ruling, which sets the stage for a later ruling on whether Microsoft's actions broke the law, largely sided with the U.S. Justice Department and 19 states that brought the ...