Microsoft Corp. CEO Satya Nadella can’t wait for people to begin using Windows 10, which his company unveiled today.

“Windows 10 marks the beginning of the more personal computing era in the mobile-first, cloud-first world,” said Nadella. “Our ambition is for the 1.5 billion people who are using Windows today to fall in love with Windows 10 and for billions more to decide to make Windows home.”

Windows 10 has a wide range of experiences designed to usher in a new era of more personal computing, as well as two new devices designed to extend the Windows experience from large screens to no screens. Windows 10 will be delivered as a service to offer a safer, innovative and updated experience for the supported lifetime of the device. A free upgrade1 for Windows 10 will be made available to customers running Windows 7, Windows 8.1 and Windows Phone 8.1, who upgrade in the first year.