CHRONOLOGY-17 years of EU, U.S. tussles with Microsoft

(Reuters) - A European Union court ruled on Monday against Microsoft's challenge to a 2004 landmark European Commission decision imposing fines and sanctions on the software giant over antitrust violations.

Following is a chronology of key events in Microsoft's 17 year legal battle with regulators and private companies from the European Union, the United States, South Korea and Hungary:

-- June 1990: U.S. agencies open investigation into Microsoft.

-- July 15, 1994: European Commission, U.S. Justice Department settle with Microsoft on ending anti-competitive practices.

-- October 20, 1997: U.S. charges 1994 settlement was violated.

-- November 24, 1997: The Commission, the EU's top antitrust regulator, settles charges over Microsoft licensing to a developer of the Unix operating system, Santa Cruz Operation.

-- April 3, 2000: U.S. judge rules Microsoft used monopoly power to block competition, later orders Microsoft be broken up.

-- August 3, 2000: Commission sends so-called "statement of objections" after Sun Microsystems complaint on licensing.

-- June 28, 2001: U.S. Court of Appeals rules unanimously Microsoft used Windows monopoly to block competition, but halts break-up.