European Commissioner for competition Neelie Kroes today denied she is conducting a personal vendetta against Microsoft. Her comments came in response to what she called 'a coordinated campaign' by Microsoft against Europe’s top antitrust regulator.

"Far from pursuing a vendetta against Microsoft, the Commission’s actions are guided by the desire to create the most innovation-friendly business climate in Europe to the ultimate benefit of European consumers," Kroes wrote in a letter in today’s Financial Times.

Earlier this month Microsoft warned that ongoing antitrust problems in Europe may delay the European launch of Windows Vista, the new version of the company’s flagship operating system.

It accused the Commission of not giving it sufficiently clear guidance on whether Vista would pass muster under European antitrust law. It also presented research it had commissioned that showed that hundreds of thousands of jobs in the European IT industry were at stake if Vista’s launch in the region was delayed.

"There appears to be a co-ordinated campaign to portray the Commission in a negative light," Kroes wrote.

"For example, I have seen it suggested that the Commission may seek to prevent Microsoft from improving the security of its operating system. This is categorically not the case," she wrote.

The Commission has been giving feedback to Microsoft since the spring about how to avoid similar antitrust problems with Vista that it experienced with its predecessor, Windows XP.

The Commission warned Microsoft that its plan to equip Vista with its own security software may amount to bundling and it urged the software company not to shut out rivals in the security software market.

In 2004 the Commission found Microsoft guilty of shutting out rivals in the media player software market by bundling its Media Player with Windows. The company was also guilty of abusing its position in the workgroup server OS market. Microsoft was fined almost €500m (about £340m) and was required to release a version of Windows without Media Player. In addition, Microsoft needed to make its server products better interoperate with competitors' offerings.

Earlier this year it was fined an additional €280.5m (about £189m) for failing to reveal details about the workings of Windows, as it was ordered to in the 2004 ruling.

Microsoft has now submitted the information, which the Commission believes is necessary for restoring competition in the market for server operating systems. The Commission will decide in the coming months whether the information is sufficient.

Meanwhile, the European Court of First Instance in Luxembourg is considering an appeal of the 2004 antitrust ruling lodged by Microsoft. The Court follows no strict timeframe. Most observers expect a ruling by next summer.