The European Commission revealed today that it plans to open proceedings against Microsoft to investigate whether the software giant has failed to comply with a 2009 browser choice commitment. Microsoft was forced to implement a browser ballot box in its Windows operating system to ensure users were presented with a choice of web browsers. The ruling followed the result of a European Union competition case that found Microsoft had abused its dominance in the market with Internet Explorer.

The Commission believes Microsoft may have failed to implement the browser choice screen correctly with Windows 7 Service Pack 1, released in February 2011. "We take compliance with our decisions very seriously," says Joaquín Almunia, a member of the European Commission. "I trusted the company's reports were accurate. But it seems that was not the case, so we have immediately taken action. If following our investigation, the infringement is confirmed, Microsoft should expect sanctions."

Other browser makers have complained at the lack of Metro browser choice in the company's upcoming Windows 8 software. If Microsoft is found guilty of breaching its legally binding commitments, it may be fined up to 10 percent of its total annual turnover. We have reached out to Microsoft for comment on the Commission's announcement and we'll update you accordingly.

Update: Microsoft has issued a statement admitting that a "technical error" prevented PCs that came with Windows 7 Service Pack 1 from seeing a browser choice screen. Microsoft is offering to extend its compliance period for an additional 15 months in an attempt to appease the European Commission.