Windows 7, the next major release of the world's most popular operating system, will be officially available to the public on 22 October.

Microsoft is hoping it can avoid the negative press that surrounded the launch of Vista, the last major Windows release, almost three years ago.

Windows 7 has been designed to be compatible with Vista so users do not have to invest in new hardware.

Customers who buy a new PC with Vista will be offered upgrades to Windows 7.