OK，Microsoft finally give us a time,It's July 29 when the Windows 10 will be available,2 months of bug fixing should work things out.
At first,let's list all Windows 10 highlight Features.
1.A start menu with more features is back.It's more convenient and powerfull.
2.Cortanta. With helpful informations and it's learning all the time.It's very personal,and you will see it everywhere.very useful and convenient.
3.Windows hello.it will be possible to log into Windows and Apps through biometrics, allowing your computer to simply recognize you instead of requiring a name and password to be typed in.
4.Microsoft Edge. A new web browser with the ability to type or hand write notes on a webpage.
5.the ability to stream games from Xbox to a Windows 10 PC.
6.free upgrade. :) :)
See all these introduction from this video
Latest OS: Make sure you are running the latest version either Windows 7 SP1 or Windows 8.1 Update.
Processor: 1 gigahertz (GHz) or faster processor or SoC
RAM: 1 gigabyte (GB) for 32-bit or 2 GB for 64-bit
Hard disk space: 16 GB for 32-bit OS 20 GB for 64-bit OS
Graphics card: DirectX 9 or later with WDDM 1.0 driver
Windows 10 is priced the same as Windows 8: Home costs $119, Pro costs $199
more information see windows.com