The European Commission accused Microsoft Corp. on Friday of stymieing competition by bundling its Internet Explorer Web browser with Windows systems, opening a new round in their expensive, years-long battle.
The executive arm of the European Union said it had reached the preliminary view that the company had prevented rival browsers from competing and had infringed EU rules on abuse of dominant position.
It added that Microsoft had eight weeks to reply to a "statement of objections" sent to the company, in which it threatened to impose a fine on the U.S. software giant if its preliminary findings were confirmed.
Microsoft has had to shell out over $1 billion in fines to the commission in the past.
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The Commission "sets out evidence and outlines its preliminary conclusion that Microsoft's tying of Internet Explorer to the Windows operating system harms competition between Web browsers, undermines product innovation and ultimately reduces consumer choice," the EU executive said in a statement.
"If the preliminary views expressed in the statement of objection are confirmed, the Commission may impose a fine on Microsoft, require Microsoft to cease the abuse and impose a remedy that would restore genuine consumer choice and enable competition on the merits."
Microsoft and the EU have engaged in a running spat over competition issues for years, and the U.S. company has been fined more than 1 billion euros in all for allegedly abusing its 95 percent dominance of personal computer systems through its ubiquitous Windows software.
In February, the EU fined the U.S. software titan a record 899 million euros for discouraging software competition, the biggest ever imposed on a corporation at the time.
Microsoft said in a separate statement on Friday that it was studying the Commission's views and did not rule out requesting a formal hearing.
It cited the Commission as saying that remedies put in place by U.S. courts in 2002 after antitrust proceedings also did not make Windows-Explorer bundling lawful.
Microsoft controls an estimated three-quarters of the Web-browsing market through Explorer.
Analysts say that the firm has diversified enormously and is now no longer so reliant on its Windows system, with revenue coming in from Xbox sales and server software.