Key Difference: Windows XP was launched in October 2001 as an upgrade to the Windows 2000 and ME operations systems. Windows 7 and Windows 8 are the two latest operating systems by Microsoft. All of the systems have been upgraded with new features and interface changes to make the systems more interesting and appealing to the users.

Windows XP operating system was launched by Microsoft for use on personal computers and is the second most popular version of Windows. Windows XP was released in October 2001. The ‘XP’ in the Windows is adapted from eXPerience, indicating enhanced user experience. Windows XP was the successor to Windows ME and Windows 2000 and was the first consumer-oriented system developed by Microsoft on the Windows NT Kernel. Windows XP offered customers a redesigned graphical user interface, which was considered more user-friendly.

The Windows XP offered customers a better Start Menu and task bar and added additional features such as translucent blue selection rectangle, drop shadows for icon labels, task-based side bars in Explorer, ability to lock taskbar, ability to group taskbar buttons together, etc. These added a more appealing look to the plain interface that was available in the older versions. The company offered two major editions of the operating system: Windows XP Home Edition and Windows XP Professional Edition. The Home Edition was for users and was pre-installed in systems, while the professional edition was offered for business users and offered advanced features. The company added a third Windows XP Media Center Edition that allowed users to incorporate new digital media, broadcast television and Media Center Extender capabilities. These were not for commercial sales but were available as OEMs. The system requires 233 MHz clock speed, 64 GB RAM, Super VGA (800 x 600) or higher resolution, 1.5 GB or higher HDD space, CD-ROM drive, keyboard and mouse and sound card, speakers or headphones.

Windows 7 was launched in October 2009 as a way to make the computer more user-friendly, as well as offer some upgrades on the already present Windows Vista system. While, Vista sought to offer many new features, Windows 7 was launched as an upgrade that was designed to work with Vista-compatible applications and hardware. The main change that was offered with Windows 7 was the new Taskbar that was dubbed as ‘Superbar’. The main reason for the launch of Windows 7 was to make a more user-friendly windows system and incorporate the new features of Windows Vista that were appealing to the people, but failed when Vista tanked.

The new features that were introduced on Windows 7 included: extended support for Vista themes, gadgets side bar that allowed users to add calendar, clock and other such gadgets on the desktop, Windows Explorer supports Libraries (which shows all virtual folders and content in a unified view), changes to the Start Menu, shut down button has been altered with more options only available if the arrow is clicked, jump lists on the taskbar when hovered on right-clicked on, search box has been extended to support items in Control Panel. Additional features include Aero Snap and Aero Shake. When Windows is dragged to the top right hand side of the screen it automatically maximized and minimizes when it is pulled away. In Aero Shake, shaking a window on the screen will only keep the shaken window active and the rest of windows will minimize. Additional keyboard shortcuts have been introduced.

Diffen.com lists the shortcuts as:

• Win+Space operates as a keyboard shortcut for Aero Peek.
• Win+Up and Win+Down are new shortcuts for Maximize and Restore/Minimize.
• Win+Shift+Up vertically maximises the current window
• Win+Left and Win+Right snap the current window to the left or right half of the current display; successive keypresses will move the window to other monitors in a multi-monitor configuration.
• Win+Shift+Left and Win+Shift+Right move the current window to the left or right display.
• Win+ + and Win+ - (minus sign) zoom the desktop in and out.
• Win+Home operates as a keyboard shortcut for Aero Shake.
• Win+P shows an "external display options" selector that gives the user the choice of showing the desktop on only the computer's screen, only the external display, on both at the same time (mirroring), or on both displays with independent desktops (extending).
• Shift + Click, or Middle click starts a new instance of the application, regardless of whether it's already running.
• Ctrl + Shift + Click starts a new instance with Administrator privileges; by default, a User Account Control prompt will be displayed.
• Shift + Right-click shows the classic Window menu (Restore / Minimize / Move / etc); right-clicking on the application's thumbnail image will also show this menu. If the icon being clicked on is a grouped icon, the classic menu with Restore All / Minimize All / Close All menu is shown.
• Ctrl + Click on a grouped icon cycles between the windows (or tabs) in the group.

Windows 7 was launched in six different editions:  Home Premium Edition, Professional Edition, Ultimate Edition, Starter Edition, Enterprise Edition and Home Basic Edition. The first three editions were available for retail sale for consumers, while the Starter edition was preinstalled by OEM, the Enterprise edition only by volume licensing, and Home Basic only to certain developing countries' markets. The Windows 7 was a hit with many of the Microsoft customers and was used widely as an operating system. The Windows 7 required a 1 GHz processor, 1 GB RAM, DirectX 9 graphics processor with WDDM driver model 1.0, 16-20 GB (depending on architecture) free disk space and a DVD-ROM drive.

Windows 8 is the latest operating system by Microsoft for its PCs, laptops and tablets. The newest OS hit the markets in October 2012 and had a whole new look. The company has launched the operating system keeping in mind the constant upgrade from keyboard and mouse PCs to touch tablets. Windows 8 was launched with touch compatibility in mind. The system sports a whole new Menu Screen, with a new ‘Live Tile’ format that is found in the Windows phones. These tiles automatically update to show users new e-mails or other information.

Windows 8 also supports new advancing technology such as USB 3.0, 4Kn Advanced Format, near field communications, cloud computing, and the low-power ARM architecture. This is the first OS that allows ARM architecture support, with the previous OS only supporting IA-32 and x86-64 architectures. It also offers built-in antivirus capabilities and advanced security features. Other features that make this OS handier are the Windows Store and app compatibility. The OS supports apps and are allow certain apps to dock on one side of the screen, while other apps can open in to proper programs. The OS also allows users to purchase and download apps from the Windows Store and use them on their laptops, PC as they would on their smartphones.

Windows 8 is offered in four editions: Windows 8, Windows 8 Pro, Windows 8 Enterprise and Windows RT. Windows 8 comes pre-loaded on the new PCs by the company. Windows 8 Pro is aimed at power users and professionals. Windows 8 Enterprise is aimed at business environments and is available through volume licensing, while Windows RT is the only edition comes preloaded on new ARM-based devices for Windows. In order to run Windows 8, the user must have certain system requirements: 1 GHz clock rate, 1-2 GB RAM (depending on the architecture), DirectX 9 graphics device WDDM 1.0 or higher driver, 1024×768 pixels display, keyboard and mouse and 16-20 GB internal storage space.

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