Microsoft finally closed the chapter on its troubled Windows Vista operating system on Thursday with the formal launch of its latest PC operating system, Windows 7 .

Steve Ballmer, chief executive, tried to shift attention to new hardware that runs Windows 7, rather than the software itself, at an event in New York to mark the launch. “Any shape, size, colour, price, environment,” he said of the many new PCs that are being launched loaded with Windows 7, including a new generation of touch-screen machines.