Microsoft Corp.'s rivals renewed their call Friday on EU regulators to act against what they say are "illegal practices", alleging that the new Vista operating system is the company's attempt to extend its monopoly to the Internet.

They asked the European Commission to take a decision "as fast as possible" on a complaint they filed last February. It had accused Microsoft of working to keep its existing monopolies and trying to extend its market dominance into other areas, including Web-based computing.

Microsoft had no immediate comment beyond saying that the rivals, represented by the group the European Committee for Interoperable Systems, were not saying anything new. The company has described the group as a front for IBM Corp. and other rivals that have constantly tried to use regulatory complaints to their business advantage.

The ECIS said Microsoft's XAML markup language — which it said was positioned to replace the current Web page language HTML — was designed "from the ground up to be dependent on Windows".

"The very same practices the European Commission found to be illegal almost three years ago have now been implemented in Vista," the ECIS said.

An ECIS spokesman, lawyer Thomas Vinje, said Microsoft was seeking to impose its own Windows-dependent standards and displace existing ones.

"The end result will be the continued absence of any real consumer choice, years of waiting for Microsoft to improve — or even debug — its monopoly products, and of course high prices," he said.

ECIS represents IBM, Nokia Corp., Sun Microsystems Inc., RealNetworks Inc. and Oracle Corp. along with smaller software companies such as Web browser maker Opera Software ASA and two Linux operating system businesses — Red Hat Inc. and Linspire.

The complaint the group filed in February 2006 alleges monopoly abuse in sectors not covered by the EU's 2004 antitrust ruling. That decision found Microsoft had abused its position by bundling media software into its Windows desktop software and squeezing rival media players out of the market.

As a remedy, the EU ordered Microsoft to share communications code with rivals to make their software work smoothly with Windows. It fined the company last July for dragging its feet over supplying the "complete and accurate" data required.

These interoperability conditions will apply to all future versions of Windows — including Vista.

Microsoft challenged the regulators' conclusions and is awaiting a ruling from the EU's Court of First Instance to back or strike down all or part of them.

Under threat of further EU action, Microsoft in October said it had made changes to Vista's search service and security system and had an international standards organization look at its new PDF-type file format.

The Commission had highlighted possible antitrust problems with Vista's range of functions, fueled by comments from other information technology companies.