Windows 10. Do great things.
The Windows you know, only better

Windows 10 feels familiar so you can get more done from the get‑go. The Start menu is back with space to pin your favorite apps. And simple navigation means you don't need to spend much time learning anything new.
Always up‑to‑date

You won't have to wonder if you have the latest features or security updates. Windows automatically delivers updates, when they're ready, directly to your device.


Cortana’s got your back

Cortana is your truly personal digital assistant who works across all your devices to help get things done.
Rule the web

Project Spartan is an all‑new browser built to deliver a better web experience. You can write directly on webpages from your PC, read articles distraction‑free, and save your favorites to read offline later.
Take your gaming further

With Xbox on Windows, play and connect with your games and friends. Everywhere.
Universal Apps, including Office

The Store in Windows 10 is a one-stop shop for hundreds of thousands of apps including games, music, videos, as well as a new version of Office.

article at http://windows.microsoft.com/en-us/windows-10/about