 "Windows10")
"Beginning July 29, 2015, Windows 10 will be available in 190 markets globally as a free upgrade to customers running on Windows 7 and Windows 8.1," Microsoft said in a statement.
Built with feedback and testing of over four million people around the world, Windows 10 marks the beginning of a new era of personal technology, designed to empower people to do great things, it added.
"We designed Windows 10 to create a new generation of Windows for the 1.5 billion people using Windows today in 190 countries around the world," it said.
This will be the last major release of the 29-year-old operating system before Microsoft switches service model with updates being rolled out, like rival OS X for Apple Macs.
Unlike the previous versions, Windows 10 is designed to work across all Microsoft devices, including desktops, laptops, tablets, smartphones, Xbox console and HoloLens, Microsoft's new wireless holographic headset.
Microsoft is also replacing Internet Explorer with Edge on Windows 10, while its voice-controlled digital assistant 'Cortana' will also make its debut beyond smartphones to compete with Apple's Siri and Google's Now.
Windows 10 is faster than before, with quick startup and resume. Microsoft claims that the new OS provides the most secure platform ever, including Windows Defender for free anti-malware protection.
