The commission's investigation into Microsoft's Web-surfing software began a year ago, after the Norwegian browser-maker Opera Software filed a complaint. Opera argued that Microsoft hurt competitors not only by bundling the software, in effect giving away the browser, but also by not following accepted Web standards.
That meant programmers who built Web pages would have to tweak their codes for different browsers. In many cases, they simply designed pages that worked with market-leading Internet Explorer but showed up garbled on competing browsers.