Microsoft will make changes to its Vista operating system to prevent potential litigation after Google accused it of violating a 2002 antitrust agreement reached with the Justice Department, the company said Wednesday, according to dpa. The change will affect the desktop search feature that Google complained violated the anti-trust agreement because it is difficult to disable and makes Google's desktop search product slow to a crawl. Google's 49-page complaint had been rejected by the Justice Department but was viewed favourably by several states, including California. It came as the two companies are locked in a fierce competition and after Microsoft asked anti-trust regulators to examine Google's 3.1 billion dollar purchase of online ad service DoubleClick Inc. Microsoft denied Google's anti-trust charges but said it will change the way Vista's search product behaves when it releases the first software upgrades for before the end of 2007. The alteration will allow users to select a default search programme, just as they can with Web browsers, media players, and security programmes, while maintaining the general ability of Microsoft's Vista search to search from within the Start Menu. Microsoft also will make information available to developers to optimize the performance third-party search products. "We're pleased we were able to reach an agreement with all the states and the Justice Department that addresses their concerns so that everyone can move forward," Microsoft general counsel Brad Smith said in an e-mail. "This agreement - while not perfect - is a positive step towards greater competition in the software industry," California Attorney General Edmund G Brown Jr said in a statement. "It will enhance the ability of consumers to select the desktop search tool of their choice."