European Union (EU) antitrust regulators announced Tuesday morning that they were investigating Microsoft for not complying with an order that requires the company to give users a choice of web browsers in Windows. But Microsoft immediately admitted that it was guilty, claiming that it was not in compliance because of a “technical error,” and apologized. The firm could now face massive fines as a result.

The investigation is apparently historic: According to the European Commission (EC), this is the first time it will have to punish a company that hasn’t met its antitrust commitments. Microsoft has been out of compliance since February 2011.

"We take compliance with our decisions very seriously,” Competition Commissioner Joaquin Almunia said during a press conference Tuesday. “And I trusted [that Microsoft’s] reports [to us] 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.”

Those sanctions could be has high as $7 billion because the EU can fine Microsoft up to 10 percent of its global annual revenues.

According to a 2009 antitrust order, Microsoft is required to offer customers in Europe a choice of web browsers in Windows. It implemented this change in February 2010 via a so-called browser ballot screen that appeared in Windows 7. But after receiving complaints that this ballot screen is no longer included in Windows 7, the EU began investigating the company. And the EU found that Windows 7 hasn’t delivered the ballot screen since February 2011, when Service Pack 1 (SP1) for Windows 7 was released.

Amazingly, Microsoft has already admitted that it isn't complying with the order. But the company claims this is due to a “technical error” only, not a secret plan to thwart antitrust regulations.

"Due to a technical error, we missed delivering the [browser ballot screen] software to PCs that came with the Service Pack 1 update to Windows 7," a Microsoft statement reads. “While we have taken immediate steps to remedy this problem, we deeply regret that this error occurred and we apologize for it.”

Microsoft says it is now delivering the ballot screen with Windows 7 and has offered to extend its compliance period another 15 months in order to match the time period in which the screen was unavailable to customers.