Microsoft has again attracted the attention of competition investigators - this time through a relationship with Corel, a Canadian software provider.

Federal anti-trust investigators are looking into an alliance between Microsoft and Corel to determine whether their relationship reduces competition.

Corel publishes the popular WordPerfect word-processing software, one of the few competitors to Microsoft's Word for Windows software.

The US Justice Department has asked for all of Microsoft's internal documents relating to the alliance.

We are complying and cooperating with the government to provide them with any information they need

Microsoft

"We received a subpoena dealing with the Corel issue," said a Microsoft spokesman.

"We are complying and cooperating with the government to provide them with any information they need and request," he added.

Microsoft has invested $135m in Corel.

The WordPerfect software is important for competition because it can be used on a computer operating system called Linux, which competes with Microsoft's Windows system.

The investigation began in January, according to reports in the newspaper The Wall Street Journal.

This was during a period when Microsoft was preparing its appeal against a federal court decision that the company had violated anti-trust laws.

A new president

That long running case concluded with the ruling that Microsoft had abused its dominant market position in computer operating systems.

Microsoft hopes on appeal to overturn that ruling and so avoid the penalty imposed - that it must be split into two companies.

News of the investigation has surfaced as Microsoft named Rick Belluzzo as its new president and chief operating officer.

Mr Belluzzo replaces the current chief operating officer, Bob Herbold, who is retiring.

Rick Belluzzo becomes president after joining Microsoft 18 months ago

"Rick is stepping up to an even more crucial role in Microsoft's leadership team," said chief executive officer Steve Ballmer.

Mr Belluzzo joined Microsoft in September 1999 from Silicon Graphics where he was chief executive.

In his new position, Mr Belluzzo will focus on business strategy and sales, marketing and business development.

He will also be responsible for developing non-PC businesses, as Microsoft looks to strengthen its position in the handheld and games console market.

"As Rick transitions to his broader set of responsibilities, I will spend more time focusing on Microsoft's strategic direction and working closely with Bill (Gates) and the leaders of our product teams," said Mr Ballmer.

Steve Ballmer: "Rick is stepping up to an even more crucial role"

In a statement, Mr Gates said that "Rick's proven management style will be a big plus in the years ahead."

Last year Mr Gates stepped down as chief executive and became chief software architect instead.

Since starting at Microsoft as a group vice president for the consumer group, Mr Belluzzo has served more recently as group vice president of the personal services and devices group.

Mr Belluzzo has worked in the past on the MSN website, the Xbox video console, the Ultimate TV service and the .Net web-based services division.