Microsoft was accused of failing to take accusations of abusing market dominance seriously enough as a three-day hearing with European regulators began behind closed doors yesterday.
Michael Hausfeld, the lawyer who sued the software giant on behalf of consumers, said in Brussels of a deposition by Microsoft's chief executive Steve Ballmer: "We asked him if he has any understanding of the word monopoly. He actually laughed and said: 'Yes, I play it with my children.' I don't think that's an indication of someone who takes his obligations seriously."
Thomas Vinje, a lawyer for the Computer and Communications Industry Association that represents Microsoft's rivals, added that Microsoft had set up a "Hollywood theatre" in the EU building. Microsoft used video and computer presentations during antitrust hearings in Washington.
The EU Competitions Commissioner Mario Monti could fine Microsoft and order it to change its Windows software to allow rivals to run multimedia products such as music and video.
Microsoft told Mr Monti at yesterday's hearing that it had not prevented rivals from running their products through Windows servers.