Microsoft, which expressed pleasure at Friday's US antitrust ruling, is likely to be disappointed in its hopes that the US decision will set the tone for a similar ruling from European antitrust regulators, according to the software giant's critics.

US district judge Colleen Kollar-Kotelly approved a settlement between Microsoft, the Justice department and nine states which means Microsoft must also offer to license intellectual property rights to computer makers before final versions of Windows are released.

The ruling also prohibits the company from retaliating against computer makers or independent software makers that consider "developing, distributing, promoting, using, selling or licensing any software that competes with Microsoft platform software or any product or service that distributes or promotes any non-Microsoft middleware".

But critics of Microsoft said that the European case is "fundamentally different" from the case Judge Kollar-Kotelly ruled on last Friday.

In the European Union, Microsoft is accused of having violated antitrust rules by using illegal practices to gain a dominant position in the market for low-end server operating systems through its influence on the market for personal computer operating systems.

The company is also accused of bundling some so-called middleware functions, such as its Media Player software, into Windows OSs (operating systems).

The European case is the result of two separate antitrust investigations into the software group. The first case was sparked by a complaint by Sun Microsystems in 1998, alleging that Microsoft was using Windows to muscle rivals out of the server software market.

In February 2000, the Commission launched a separate investigation on its own initiative to see if Microsoft was doing the same thing with the then latest version of the OS, Windows 2000.

As with the first case, the Commission believes that Microsoft may have withheld key interoperability information that vendors of alternative server applications needed in order to allow their products to communicate with Microsoft's dominant PC and server software.

In March this year, Microsoft said it was offering to give competitors access to some of the interoperability information, but rivals said it was not nearly enough to restore fair competition. The Commission has given no indication whether or not the offer goes far enough to overcome the EU's concerns.

On Sunday, Microsoft's associate general counsel for Emea (Europe, Middle East and Africa), Horacio E. Gutiérrez said he hoped the European Commission uses the US decision as "a reference point" as it works to resolve the case it began against the company at the end of 1998.

Gutiérrez said he expects the Commission, the European Union executive body charged with policing competition in the 15-country block, to analyse the US ruling closely, but he added that the situation is not the same in Europe. "The law is different, the decision makers are different," he said.

The EU declined to make any comment on the case.