The decision by the EU Court of First Instance in Luxembourg on Wednesday (Dec. 22) means Microsoft must sell a European version of Windows without the Windows Media Player.

Until a final appeal in the antitrust case is heard in the next two years, the software giant will also be required to disclose parts of its Windows source code.

Microsoft's appeal stems from a March ruling by the EU's Competition Committee that imposed sanctions and a large fine for violating European antitrust laws. Microsoft was seeking a preliminary injunction that would have delayed the ruling taking effect while its appeal was being heard.

"Microsoft has not demonstrated specifically that it might suffer serious and irreparable damage," Court of First Instance President Bo Vesterdorf said.

Nicholas Economides, an economics professor at New York University who specializes in antitrust law, said the Luxembourg court's ruling upholding penalties imposed by the EU means Microsoft will have to produce a stripped-down version of Windows in Europe and pay the largest fine in EU history — $665.4 million.

However, the ruling by the second highest EU court can still be appealed to the European Court of Justice.