A big change to the look and feel of the world's most widespread PC operating system
Windows 8 is the newest version of the Microsoft operating system (OS) we're all familiar with on our laptops and desktop PCs. It's no exaggeration to say that this latest edition is the biggest revamp since Windows 95.
Watch: Windows 8 tips
The biggest change is the interface, which has been designed to work with a touchscreen or with a keyboard and mouse. Microsoft claims this makes it perfect for tablets and more familiar computers. It had the development name 'Metro' but is now referred to simply as 'Windows 8'.
For our review of Windows 8, we installed it on an HP all-in-one PC with a touchscreen and a keyboard and mouse to see how well it works on a non-tablet computer.
We tested Windows 8 on the HP Touchsmart 520-1030UK all-in-one PC
The biggest single change is the Start menu. It has been replaced by a new Start screen, a change that is going to leave may Windows users asking where has the start button gone?'.
Users of Windows Phone 7 will find it instantly familiar, though. The large and colourful Live Tiles take the place of icons. You can pick and choose which tiles you want to have ‘pinned' to your Start screen with the rest accessible from the ‘all apps' button.
Besides opening programs, the tiles also continuously update to show new information. For example the Calendar tile will show your next upcoming appointment, while the Mail tile shows how many unread emails await your attention.
The Start screen scrolls horizontally instead of vertically. On a touchscreen PC or tablet you would swipe the screen to scroll, but it's also possible to scroll using a mouse wheel, scroll bar or the arrow keys.
All of the tasks that used to be accomplished using the Start menu are now done from the Start screen, from accessing settings to quickly searching for programs and files. The simplified, colourful interface is startlingly different if you're used to Windows 7.
What has happened to the Start menu?
In fact, the Start screen isn't just a Start menu replacement – it's a whole new way of using a Windows computer. Software that is designed to be compatible with the Windows 8 interface, such as Internet Explorer or the email program, take over the entire screen. None of the menus and toolbars you will be familiar with are to be seen.
Extra buttons and controls are accessed by either swiping down from the top or the bottom of the screen if you have a touchscreen or by clicking the right mouse button.
Programs and apps designed to work with the Windows 8 interface can now be bought from Microsoft's Windows app store, but the selection of apps at the time of writing is sparse. Although this will undoubtedly improve over time, it's telling that the upcoming Microsoft Office 2013 won't use the new Metro interface.
App-ortunity: the Windows 8 app store
System-wide options, such as getting back to the Start screen or searching, are accessed from another new tool called the Charms bar. To make this appear, swipe from the right-hand side of your touchscreen or hover the mouse at the top right-hand side of the screen.
There is no taskbar in Metro programs, so to see which programs are currently open, you have to use a fiddly touchscreen gesture on the left-hand edge of the screen or hover the mouse there. Bizarrely, the clock is no longer visible in Metro apps unless you first activate the Charms bar.
Frustrating Windows 8 interface
Although Windows 8 feels considerably smoother and more responsive on a touchscreen than Windows 7, the new way of working in the Start screen and Windows 8 apps is initially strange and frustratingly confounding when using a keyboard and mouse. You do get used to it, but the preinstalled apps are basic and the stripped-down, full-screen interfaces fail to take advantage of a PC's high-resolution screen.
It is possible to have two Metro apps running side-by-side, but the second app can only run in a narrow strip on either the left- or right-hand side of the screen so this works best with apps that have lists of information, such as a Twitter or email program. Annoyingly, the touchscreen gestures and mouse controls for activating this split screen mode are fiddly.
Seeing double: running two Metro apps side-by-side in Windows 8
The traditional desktop and more familiar programs are still present in Windows 8 though. Click the Desktop icon and the old-style interface returns. Even if you're dedicated to the new Start screen and Metro apps, the old desktop is actually still essential for even the most basic tasks from accessing USB memory keys to installing drivers for printers and other peripherals, as well as for using existing non-Metro programs.
This constant switching back and forth feels disjointed and inconsistent for experienced users and can be confusing for novices. This is especially true when accessing files from within programs. Metro apps have a completely different interface for opening and saving files compared to traditional programs.
Space the final frontier: opening and saving files in a Windows 8 Metro app
There's still no Start menu in the traditional interface though – pressing the Start key on your keyboard activates the Start screen. Hover the mouse where the Start button would be and a small thumbnail of the Start screen appears – click it to use the Start screen.
With a Ribbon on top: Windows Explorer in Windows 8
Tweaks to the traditional desktop interface include the addition of tabbed Microsoft Office-style Ribbon toolbars to Windows Explorer. Although this can look intimidating, it does ultimately make all the various commands and options easier to find.
Users of multiple monitors will be pleased to find a couple of new features. It's possible to have the Start screen on one display and the traditional desktop on another. Different monitors can also have their own taskbars, so a monitor's taskbar can show only icons for programs open on that particular screen.
One undeniably useful feature that needs to be taken further is Windows' integration with Microsoft's cloud services. You're encouraged to sign in with your Microsoft account when installing Windows 8.
Doing so allows you to seamlessly synchronise your settings, but not apps or files stored on your hard disk, between multiple Windows 8 computers. Files stored on the Microsoft Skydrive online storage service will appear on all your Windows 8 computers automatically.
Different versions of Windows 8
The standard version of the new operating system, simply called Windows 8, will suit most home users and is available as a download for the low price of £25.
However the Media Centre feature from Windows 7 for recording TV is now an optional add-on. There are Pro and Enterprise versions with specialised features aimed at users who work in medium and large businesses.
There's also a special version called Windows RT that's only available preinstalled on tablets that use power-efficient ARM processors rather than traditional Intel or AMD chips. It's identical to Windows 8, but can't run existing Windows 8-interface programs.
Windows 8 is a big gamble for Microsoft. In changing an interface that millions of people have become familiar with over the course of almost 20 years, it risks alienating many of its customers. The increasing shift from sales of laptops to those of tablets means that Microsoft has to find a way to make Windows work with touchscreens - something Windows 7 completey failed to do.
Whether it can do better than Apple or Android on that type of device will be down to two things: the quality of the apps that developers produce and the speed with which customers become familiar with the Windows 8 interface.
But on the desktop and laptop, with touch or without, the Windows 8 interface is confusing at first and the access controls for some of the important tools are fiddly. That's a shame, as there are some interesting new features behind it.
Watch our video guides to Windows 8
Read more reviews
Some interesting new features and a rock-bottom price, but the new touch-focused Windows 8 interface is woefully ill-suited for a laptop or desktop PC. For traditional computers, stick with Windows 7
Cheap; Integrates with Microsoft cloud services; Traditional interface still available
New interface is awkward and disjointed using keyboard and mouse
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