Microsoft releases Windows 10 as a free upgrade and also HoloLens, which looks like a wireless visor and allows users to see three-dimensional renderings of computer-generated images. The initial Windows 10 release is limited. The public might not be able to download it until August.
As a way to distance itself from the widely disliked Windows 8, the company is skipping the release of Windows 9.
The new operating system will be issued as a free upgrade to users of Windows 7, Windows 8.1 and Windows Phone 8.1.
Reuters reports that Windows only features on roughly 15 per cent of computing devices, including phones and tablets, and is largely irrelevant for many consumers. The free release is seen as the company's way of catching up with Apple Inc. and Google Inc., which regularly update their software for users at no charge. HoloLens takes on Facebook Inc's Oculus and Google's Glass project.
Announcing Windows 10 in Sep 2014, Microsoft explained the change to Windows 10 as a move to unify use of all kinds of device and to "bring back familiarity". The original version of Windows 8 did not prove popular because it did away with some familiar elements of the desktop version of the operating system. By contrast, Windows 7 has been available since late 2009 and is still very popular among users.
UPDATED JUL 5 TO SHOW EARLIER RELEASE DATE AND LIMITED RELEASE. THE PUBLIC WON'T BE ABLE TO DOWNLOAD IT UNTIL AUGUST.
Date written/update: 2015-07-07