We have seen leaked images and downloads of Windows 8 OS but this time Microsoft has finally unveiled the very first video demonstration showing us what's in the store for upcoming major upgrade to Windows platform.

The video demos the next generation of Windows, internally code-named “Windows 8”. According to the official announcement the "Windows 8" based PC is really a new kind of device completely revamped from the chip to the user-interface, one that scales from touch-only small screens through to large screens, with or without a keyboard and mouse.

The demo shows the metro tile based user-interface for a new generation of touch-centric hardware. Fast, fluid and dynamic, the experience has been transformed while keeping the power, flexibility and connectivity of Windows intact - watch the full video after the jump.

Here are a few aspects of the new interface we showed today:

• Fast launching of apps from a tile-based Start screen, which replaces the Windows Start menu with a customizable, scalable full-screen view of apps.

• Live tiles with notifications, showing always up-to-date information from your apps.

• Fluid, natural switching between running apps.

• Convenient ability to snap and resize an app to the side of the screen, so you can really multitask using the capabilities of Windows.

• Web-connected and Web-powered apps built using HTML5 and JavaScript that have access to the full power of the PC.

• Fully touch-optimized browsing, with all the power of hardware-accelerated Internet Explorer 10.