The European Commission has fined US software firm Microsoft £680m for failing to comply with a 2004 order to stop its monopolistic practices.
The ruling, which applies to how Microsoft sold server software and products such as media players, comes on the day Microsoft launches a new server package,Windows Server 2008, and a week after it agreed to open up its application programme interfaces to third-party software developers.
The commission fined the Redmond company £680.9m after it failed to comply with a 2004 ruling that said that Microsoft was guilty of not providing vital information to rival software makers.
It also required Microsoft to disclose interface documentation that would allow non-Microsoft work group servers to achieve full interoperability with Windows PCs and servers at a reasonable price.
EU regulators said Microsoft was the first firm to break an EU antitrust ruling. The European Court of First Instance upheld this ruling last year, which ordered Microsoft to pay £376m for abusing its dominant market position.
"Microsoft was the first company in 50 years of EU competition policy that the commission has had to fine for failure to comply with an antitrust decision," competition commissioner Neelie Kroes said in a statement.
Microsoft said it is reviewing the commission's action. "The commission announced in October 2007 that Microsoft was in full compliance with the 2004 decision, so these fines are about past issues that have been resolved.
"As we demonstrated last week with our new interoperability principles and specific actions to increase the openness of our products, we are trying to focus on steps that will improve things for the future."
Read more on IT legislation and regulation
Greens in the European Parliament are calling on the European Commission to ban Microsoft from bidding on future EU procurement contracts.