Microsoft Corp. officials said yesterday that the company has spent millions of dollars preparing a version of its Windows operating system without a program for playing digital music and videos, in the event it loses its bid to postpone antitrust sanctions ordered by European authorities.

At hearings in Luxembourg scheduled for Thursday and Friday, Microsoft will try to convince a European Union judge that an order to decouple the Windows Media Player from the operating system would hobble the performance of Windows. The company wants this and other E.U. mandates postponed until it exhausts its appeals in the European court system, a process that could take years.

But Microsoft officials said yesterday in Brussels, where most E.U. agencies are based, that if the postponement is not granted, it would release a version of Windows for European markets without the media player.

"Obviously we will comply with any requirements or court orders," said Dirk Delmartino, a company spokesman.

The news represents something of a turnabout for the software giant, which has long argued in U.S. courts and to European regulators that forcing it to remove specific applications from Windows would do irreparable damage to the operating system, because various programs depend on each other to function.

In March, E.U. antitrust authorities decided to require two versions of Windows after determining that Microsoft was illegally using its Windows domination to push out competitors in the media-player market, one of the hottest sectors of computer use by consumers.

By bundling the media player with Windows, E.U. regulators found, Microsoft had an unfair advantage against rivals such as RealNetworks Inc., which primarily have to rely on users to separately download their media-playing software.

The E.U. hopes to level the playing field by making it easier for competitors to strike deals with computer makers to put their media players on the versions of Windows that don't contain Microsoft's player.

In addition to the media-player mandate, the E.U.'s competition commission also slapped Microsoft with the largest antitrust fine ever, roughly $600 million, and ordered it to disclose more of its code to rival makers of network operating systems so that the alternatives would work smoothly with Windows machines.

Microsoft's Delmartino said the stripped-down version of Windows "will not work as a normal version," but he did not specify what would and would not function.

He said developers of other software products that make use of the media-playing capability of Windows also would be hurt by having less-robust versions of the operating system in the marketplace.

In the United States, attorneys general of several states had sought a similar remedy for Microsoft's antitrust violations, but the proposal was rejected by federal courts.

Instead, in an agreement with the Justice Department, Microsoft agreed to give consumers and computer makers the ability to mask the presence of various Microsoft applications in Windows.

In the course of that case, a Microsoft executive testified that removing the Windows media player would hamper rival media players from working properly.

RealNetworks executives dispute this, and they have given demonstrations to E.U. regulators showing its player operating normally on a version of Windows with Microsoft's media player removed.

Although this week's hearings are on the largely procedural question of whether the E.U. order can be set aside pending appeals, both sides view the decision as a critical juncture in the case.

Microsoft hopes that winning a postponement might push E.U. regulators back to the negotiating table to try to settle the case. The two sides came close to an agreement before the E.U. antitrust commissioner, Mario Monti, issued his orders, but it fell through at the last minute.

"We have said repeatedly that we are committed to working these issues out in a constructive way," Brad Smith, Microsoft general counsel, said in an interview. "We hope the court provides guidance that makes it easier for all parties to sit down and hammer out a solution in an amicable way."

Rivals worry that a postponement will mean years of appeals that will result in Microsoft gaining an insurmountable chokehold on the media-playing and network-server markets.

The hearings that begin Thursday will be before Bo Vesterdorf, presiding judge of the E.U.'s Court of First Instance. The court often hears preliminary matters for the European Court of Justice, which would hear the full appeal of the case.