Windows 8 introduces significant changes to the operating system's platform, primarily focused towards improving its user experience on mobile devices such as tablets to rival other mobile operating systems like Android and Apple's iOS. Windows 8 introduces a new touch-friendly shell and user interface based on Microsoft's "Metro" design language, featuring a new Start screen with a grid of dynamically updating tiles that represent applications. The Start screen replaces the "Start menu" of earlier Windows versions. There is a new app platform with an emphasis on touchscreen input, and the new Windows Store to obtain and/or purchase applications to run on the operating system.
Speedy Boot Time
The load and boot up speed has improved significantly over Windows’ predecessors. This is partly due to the better resource allocations to applications and the system. When compared to Windows 7 desktop CPU, Windows 8 has an even speedier boot time.
How did they improve so much over Windows 7? Well, Windows 8 employs a technique of hibernating the system kernel (think of it as your OS’s resource manager) when you shut down, such that it becomes almost like a partial hibernation each time. When you reboot the system, the ‘memory’ of your previous session gets reinitialized quicker.
Innovative & Dynamic Desktop
The tiles-based interface, or the Metro UI, will be the first thing you see upon logging in to Windows 8. At first glance, the UI seems to go intuitively with touchscreen devices like tablets and smartphones. Indeed, in such devices, you tap on those apps to open them. The grid layout seems to facilitate such interactions. Needless to say, you can customize your grid by adding and arranging applications.
The coolest thing, however, is that not only does Windows 8 allows you to personalize your desktop with the organization of the apps, it is also able display real-time information through them.
Improved Search Function
Windows 8 has no search box at the bottom of the Start menu. Heck, it doesn’t even have the trademark Start menu! That doesn’t mean that there’s no convenient search function available. All you need to do is to type anything, and a search box will appear from the right and give you the results. The search capability is even stronger this time, displaying all the matching apps and files instantaneously.
You can also search within apps that utilize Windows 8′s search function. The search pane that pops out on the right of your desktop will contain the list of apps which you can conduct the search in.
The Secret Start Menu
Microsoft has replaced the old Start orb with an animated, tiled page of apps, but there's still a Start menu of sorts in place - right-click in the lower left-hand corner of the screen to bring up a menu of quick links to the Control Panel, Task Manager, programs list and others..
New in Windows 8 is File History, which works in a similar way to Apple's Time Machine technology, automatically logging older versions of your files that you can restore as and when required, The feature isn't enabled by default though.
The Easy Reinstall
The Old Reinstalling Windows used to involve messing around with product keys, DVDs and backups. It could take up half your day. The New Windows 8 streamlines the whole process, which can be completed with just a few mouse clicks.
If you've just upgraded to Windows 8, then you might still be using your old user accounts—and you may not realize the features available with the new Windows IDs. Sign in with this ID (it's the same one you use for MIcrosoft services like SkyDrive and Hotmail/Outlook.com)