Vista sales fastest ever

Microsoft has sold 40 million copies of its new operating system, Windows Vista, which was released to consumers in January, making it the company's fastest product launch ever and confounding sceptics.

The figures are a rebuke to critics who initially said Vista sales were proving lacklustre, and they pushed Microsoft shares back to the levels reached in the days before the launch.

And the announcement neatly coincided with the revelation that George Soros, the investment guru, has doubled his holding of Microsoft shares to 415,497, when they were in the doldrums a few weeks ago.