Windows 10

After successful Windows 7, Microsoft launched Windows 8 (without a start menu) aimed at touch screens failed to attract user base with desktop, Software giant tried to persuade users with more improved Windows 8.1 update, that wasn’t enough, as they’ve to develop and release Windows 10 with start menu on July 29, 2015.
Through Windows insider Program Microsoft collected feedback and made changes to insider builds in fast and slow rings, and have plans to roll out stable build to Public using RTM builds.
By offering free upgrade offer to Genuine Windows 7 and Windows 8,1 systems for a year (since launch) they aim to increase Windows 10 devices number to 1 billion in one or two years.