The European Commission fined United States computer giant Microsoft for disobeying sanctions imposed on it for anti-competitive behaviour.
A court ruling ordered Microsoft to pay almost 900 million euros for failing to comply with a 2004 ruling, that it took part in monopolistic practices.
According to the first ruling, Microsoft was guilty of not providing vital information to rival software makers.
European regulators said the 2004 investigation found that Microsoft was also guilty of freezing out rivals in server software and products such as media players.
The European Court of First Instance upheld this ruling last year, which ordered Microsoft to pay 497 million euros for abusing its dominant market position.
Last week, Microsoft announced that it would open up the technology of some of its leading software to make it easier to operate with rivals\' products.