Microsoft confirmed that it has submitted a formal response to European Union charges that tying the Internet Explorer browser to its Windows operating system violates antitrust rules.
The company can also seek a hearing before EU officials move toward a final decision that can fine a company up to 10 per cent of yearly global turnover or order it to change the way it does business.
EU regulators allege that adding Internet Explorer to Microsoft's ubiquitous desktop software was an "artificial distribution advantage which other web browsers are unable to match."
Internet Explorer is the world's most widely-used web browser, overshadowing Mozilla's Firefox, Google's Chrome and Apple's Safari.
Microsoft did not issue an official statement on its response to the charges but did say in January - when the EU filed the charge sheet - that it was committed to conducting its business in full compliance with European law.
The commission's investigation into Microsoft's web-surfing software began a year ago, after the Norwegian browser-maker Opera Software ASA filed a complaint, arguing 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.
Microsoft has touted its latest browser, Internet Explorer 8, as being fully compliant with web standards.
At the time of the complaint, Opera said it was asking EU regulators to either force Microsoft to market a version of Windows without the browser, or to include other browsers with Windows.