"There are more privileged interconnections between Vista and other Microsoft products than in earlier versions of Windows," said Thomas Vinje, attorney for a group that calls itself the European Committee for Interoperable Standards. Those "interconnections," Vinje said in an interview Friday, violate a 2004 European Commission finding that Microsoft's bundling of applications and operating systems is anticompetitive.

The ECIS, whose members include Microsoft rivals Adobe Systems, IBM, RealNetworks, Red Hat, and Sun Microsystems, filed a formal complaint with the European Commission in December, said Vinje. The group released a media statement on the move Friday.

Microsoft's bundling of its XML Paper Specification (XPS) document creation application -- a potential competitor to Adobe Acrobat -- with Vista is a prime example of the new operating system's anticompetitive features, Vinje said. "It's similar to what was prohibited by the Commission's decision in 2004 on Windows Media Player," he said.

As part of that ruling, the Commission ordered Microsoft to produce a European version of Windows XP that did not include Media Player. The Commission also fined Microsoft $613 Million. Microsoft has challenged the ruling and is awaiting a decision by the European Union's Court of First Instance.

The ECIS also is charging that interoperability standards employed by Vista will effectively lock out products from competing application providers. For example, it claims Microsoft's Extensible Application Markup Language (XAML), as opposed to the more commonly used HTML Web authoring language, "is designed from the ground up to be dependent on Windows, and thus is not cross-platform by nature," according to Vinje.

The ECIS also alleges, in a statement, that Microsoft's decision to use its Open XML file format (OOXML) within Vista and Office 2007 is a move "to displace ODF [Open Document Format], the existing ISO approved, truly open document file format."

Vinje said the European Commission has not yet responded to the group's complaint. "They may take it very seriously, or they may do nothing. We think it's very serious," he said.

For its part, Microsoft says the ECIS and its members are simply trying to use the courts to avoid competition. "We have come to expect that as we introduce new products that benefit consumers ... a few competitors will complain," said a spokeswoman for the company. She called the ECIS "a front for IBM and a few others."

Editor's note: This story was modified at 2:13 p.m. EST to add Microsoft's response.