An emboldened European Commission launched new antitrust investigations against Microsoft today. The commission will formally investigate complaints from the European Committee for Interoperable Systems, a coalition of Microsoft rivals; and Opera Software, the Web browser maker that aired its concerns about Internet Explorer last month.

Although the complaints from Opera and ECIS were publicly known, the commission this morning also cited separate allegations about Microsoft using Windows' position to the unfair advantage of its products in other markets, including desktop search and Windows Live online services.

The commission says it will "focus on allegations that a range of products have been unlawfully tied to sales of Microsoft's dominant operating system."

The announcement follows last year's court judgment that largely upheld the commission's March 2004 antitrust ruling against the company over its activities in the digital-media player and computer-server markets. The commission today cited that decision as precedent as it announced the opening of the formal investigations. Excerpts from the news release:

As regards interoperability, in its Microsoft judgment of 17 September 2007, the Court of First Instance confirmed the principles that must be respected by dominant companies as regards interoperability disclosures. In the complaint by ECIS, Microsoft is alleged to have illegally refused to disclose interoperability information across a broad range of products, including information related to its Office suite, a number of its server products, and also in relation to the so called .NET Framework. The Commission's examination will therefore focus on all these areas, including the question whether Microsoft's new file format Office Open XML, as implemented in Office, is sufficiently interoperable with competitors' products.

As for the tying of separate software products, in its Microsoft judgment of 17 September 2007, the Court of First Instance confirmed the principles that must be respected by dominant companies. In a complaint by Opera, a competing browser vendor, Microsoft is alleged to have engaged in illegal tying of its Internet Explorer product to its dominant Windows operating system. The complaint alleges that there is ongoing competitive harm from Microsoft's practices, in particular in view of new proprietary technologies that Microsoft has allegedly introduced in its browser that would reduce compatibility with open internet standards, and therefore hinder competition. In addition, allegations of tying of other separate software products by Microsoft, including desktop search and Windows Live have been brought to the Commission's attention. The Commission's investigation will therefore focus on allegations that a range of products have been unlawfully tied to sales of Microsoft's dominant operating system.

Microsoft's statement, via spokesman Jack Evans: "We will cooperate fully with the Commission's investigation and provide any and all information necessary. We are committed to ensuring that Microsoft is in full compliance with European law and our obligations as established by the European Court of First Instance in its September 2007 ruling."