Microsoft has confirmed that computer manufacturers will be able to set Google or other non-Microsoft search engines as the default search service in Vista - the next version of its flagship Windows operating system.
Brad Smith, Microsoft senior vice-president, said the software giant is adopting a voluntary set of principles to guide development of its market-dominating operating system in a manner that promotes competition.
He acknowledged that eight of the 12 principles come from the company's 2002 anti-trust settlement with the US Department of Justice.
"If a computer manufacturer wants to set a competing search service so that service runs by default, they can do so," Mr Smith said in a speech to the New America Foundation, a Washington public policy institute.
Microsoft's plan to include a search service to compete with industry leader Google in the next version of Windows has caused concern that the two companies may engage in the same kind of legal fight as the Microsoft-Netscape browser war in the late 1990s.
Microsoft plans to release Vista - which has been available in a trial Beta form for some little while - to business customers in November before a wider general release in January.
In addition to allowing manufacturers to set Google and other programs as a default, the new "Windows Principles" include a promise to let computer makers "remove the means by which end users access key Windows features, such as Internet Explorer and Windows Media Player."
Microsoft also said it would not "retaliate" against computer makers that choose nonMicrosoft software and to take other steps to help third party software developers and customers.
US Senator Orrin Hatch, a Republican who describes himself as one of Microsoft's most vocal critics on anti-trust matters, said in a statement he was "encouraged by the changes they are making to their business model in order to comply with the US consent decree."
Other Microsoft critics were more sceptical. Ken Wasch, president of the Software & Information Industry Association, said a key factor for software makers is whether Microsoft will charge computer manufacturers less for Windows if they choose to strip out Microsoft's internet browser, media player or other software.
"There is no economic incentive whatsoever for the nonMicrosoft products to be included by the OEM," without such price differences, Mr Wasch said.
Brad Smith said Vista will be sold to computer makers in five different configurations. He did not offer details how the versions would differ or which Microsoft applications they would include.
"Users are in charge of their own machines," Mr Smith said. "Microsoft will design and develop and distribute Windows so that computer manufacturers configure it - they get to choose and select the defaults, but users will always be in charge."
Meanwhile, Microsoft has beaten the BBC to be crowned the UK's top consumer brand.
The nation's top 500 "superbrands" list reflects ongoing changes in customers' taste.
Recent newcomers Google, Dyson and Nokia all feature in the top 20 favourites. They rub shoulders with more established brands such as British Airways, Heinz and M & S.
A group of industry experts picked 650 brands from a list of 1,200 on the basis of their quality, reliability and distinctiveness within the sector.