Microsoft has responded to EU regulators’ latest competition concerns with only hours to go before the European Commission’s deadline for the US software giant ran out.

The EU competition watchdog had given Microsoft until today to answer its most recent concerns, threatening millions of euro in daily fines if regulators were not satisfied with the  company’s answer.

The Commission accused Microsoft of charging too much for licences for key information on its Windows operating system other programmers need to make rival products as required by a March 2004 EU ruling.

“We continue to seek to resolve these recent issues,” said Microsoft general counsel Brad Smith said in a statement.

“We need greater clarity on what prices the Commission wants us to charge, and we believe that is more likely to come from a constructive conversation than from a formal hearing,” he added.

In 2004, the Commission fined the US company a record 497 million euros for abuse of its dominant market position through its Windows operating system.

It also ordered Microsoft to sell a version of Windows without Media Player software and to divulge the software protocols underpinning Windows for makers of rival products.

Microsoft challenged the 2004 ruling in the EU’s second-highest court last April and the judges are expected to hand down a decision  in the first half of this year.

Frustrated with this defiance, the Commission last July slapped daily fines adding up to 280.5 million euros over the six-month period of the penalty for failing to fully respect the competition  ruling. Microsoft has paid that fine but is appealing against the charges.