Microsoft's internet browser and media player are being targeted in a Chinese antitrust probe. Microsoft has not been fully transparent with information about its Windows and Office sales, but is willing to cooperate with ongoing investigations, Zhang Mao, the head of the State Administration for Industry and Commerce (SAIC), told reporters at a briefing in Beijing on Tuesday.

As Windows became the world's dominant operating system in the 1990s and 2000s, the issue of how Microsoft bundled its web browser and media player became the focus of respective antitrust cases brought by U.S. and European authorities.

Microsoft settled in 2001 with the U.S. Department of Justice a case centering around whether it could bundle its flagship Internet Explorer browser with Windows.

In 2004, the European Union ordered Microsoft to pay a 497 million euro ($656 million) fine and produce a version of Windows without the Windows Media Player bundled. The fine was later increased to nearly 1.4 billion euros.

The SAIC said earlier this month that Microsoft had been suspected of violating China's anti-monopoly law since June last year in relation to problems with compatibility, bundling and document authentication for its Windows operating system and Microsoft Office software.