The European Commission has laid out specific antitrust concerns it has about Vista, Microsoft's long awaited new operating system, Commission spokesman Jonathan Todd said Wednesday.

"We are concerned about the possibility that Vista will include software elements which are available separately either sold by Microsoft or by other software companies," Todd said. "There is also the possibility that we won't have all the technical information needed for competitors to make their software interoperable with Vista," he added. The Commission said it told Microsoft about these concerns in a letter sent last week to Chief Executive Officer Steve Ballmer. Microsoft declined to comment on the letter, which it said it hasn't yet received.

The concerns echo the findings in the Commission's 2004 antitrust ruling against Microsoft, which found Microsoft guilty of bundling its Media Player software into the Windows operating system. It also ruled that the software giant had stunted competition by not allowing competitors the information needed to make their servers interoperate with PCs running Windows. The concerns about Vista, which is due to go on sale to consumers at the beginning of next year, include plans to bundle in an Internet search function, a DRM (digital rights management) program and software for creating a fixed document format comparable to the PDF format, and security features, Todd said.