Windows 7 (formerly codenamed Blackcomb and Vienna) is the latest version of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, netbooks, tablet PCs and media center PCs. Windows 7 was released to manufacturing on July 22, 2009, with general retail availability set for October 22, 2009, less than three years after the release of its predecessor, Windows Vista. Windows 7's server counterpart, Windows Server 2008 R2, is slated for release about the same time.

Unlike its predecessor, which introduced a large number of new features, Windows 7 is intended to be a more focused, incremental upgrade to the Windows line, with the goal of being fully compatible with applications and hardware with which Windows Vista is already compatible. Presentations given by Microsoft in 2008 focused on multi-touch support, a redesigned Windows Shell with a new taskbar, a home networking system called HomeGroup, and performance improvements. Some applications that have been included with prior releases of Microsoft Windows, including Windows Calendar, Windows Mail, Windows Movie Maker, and Windows Photo Gallery, will not be included in Windows 7; some will instead be offered separately as part of the free Windows Live Essentials suite.

Windows 7 includes a number of new features, such as advances in touch and handwriting recognition, support for virtual hard disks, improved performance on multi-core processors, improved boot performance, DirectAccess, and kernel improvements. Windows 7 adds support for systems using multiple heterogeneous graphics cards from different vendors (Heterogeneous Multi-adapter), a new version of Windows Media Center, a Gadget for Windows Media Center, improved media features, the XPS Essentials Pack and Windows PowerShell being included, and a redesigned Calculator with multiline capabilities including Programmer and Statistics modes along with unit conversion. Many new items have been added to the Control Panel, including ClearType Text Tuner, Display Color Calibration Wizard, Gadgets, Recovery, Troubleshooting, Workspaces Center, Location and Other Sensors, Credential Manager, Biometric Devices, System Icons, and Display. Windows Security Center has been renamed to Windows Action Center (Windows Health Center and Windows Solution Center in earlier builds) which encompasses both security and maintenance of the computer. The default setting for User Account Control in Windows 7 has been criticized for allowing untrusted software to be launched with elevated privileges by exploiting a trusted application.Microsoft's Windows kernel engineer Mark Russinovich acknowledged the problem, but noted that there are other vulnerabilities that do not rely on the new setting.

The taskbar has seen the biggest visual changes, where the Quick Launch toolbar has been replaced with pinning applications to the taskbar. Buttons for pinned applications are integrated with the task buttons. These buttons also enable the Jump Lists feature to allow easy access to common tasks. The revamped taskbar also allows the reordering of taskbar buttons. To the far right of the system clock is a small rectangular button that serves as the Show desktop icon. This button is part of the new feature in Windows 7 called Aero Peek. Hovering over this button makes all visible windows transparent for a quick look at the desktop. In touch-enabled displays such as touch screens, tablet PCs, etc., this button is slightly wider to accommodate being pressed with a finger. Clicking this button minimizes all windows, and clicking it a second time restores them. Additionally, there is a feature named Aero Snap, that automatically maximizes a window when it is dragged to either the top or left/right edges of the screen. This also allows users to snap documents or files on either side of the screen to compare them. When a user moves windows that are maximized, the system restores their previous state automatically. This functionality is also accomplished with keyboard shortcuts. Unlike in Windows Vista, window borders and the taskbar do not turn opaque when a window is maximized with Windows Aero applied. Instead, they remain transparent.