The European Commission, fresh from a major court victory over Microsoft, launched new antitrust investigations into the software giant on Monday on suspicion it abused its market dominance to favor its Web browser and Office product.
The European Union executive said it would look into complaints from rivals that Microsoft unfairly tied its Web browser to the Windows operating system and made it harder for software rivaling Office and Outlook to work with Windows.
“This initiation of proceedings does not imply that the Commission has proof of an infringement. It only signifies that the Commission will further investigate the case as a matter of priority,” the Commission said.
It was acting after receiving a complaint from Opera, a Norwegian maker of a Web browser, which competes with Internet Explorer.
Another complaint was lodged by a software makers group, the European Committee for Interoperable Systems, which said Microsoft did not disclose enough interoperability information for a range of products that compete with Office and Outlook.
Microsoft Office, a huge moneymaker for the company, provides word processing, spreadsheets and other standard office software.
Outlook and its server software provide e-mail services and allow groups to collaborate, for example by setting meetings together over e-mail.
The move represents a new front in a long-running battle between Brussels and the U.S. software maker.
That tussle came to a head last September when the EU’s No. 2 court threw out Microsoft’s appeal against a landmark ruling by the Commission in 2004 that the company illegally tied audiovisual software to Windows. The Opera complaint is based on that precedent.
The court also ruled that Microsoft failed to provide interoperability information needed for server software used by office workers for printing and signing on.