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Microsoft launches Windows 8 and tablet

25 October 2012 Last updated at 19:25 BST

Microsoft has launched the latest version of its Windows software and a tablet computer - both designed to give Apple a run for its money.

Microsoft's chief executive, Steve Ballmer, has acknowledged it is a "pivotal time" for the company.

The BBC's technology correspondent, Rory Cellan-Jones, has been in Seattle for the launch of Windows 8.