Microsoft Windows, computer operating system (OS) developed by Microsoft Corporation to run personal computers (PCs). Featuring the first graphical user interface for IBM-compatible PCs, Microsoft Windows soon dominated the PC market. Learn more about the operating system, including its various versions.
Screwdriver, tool, usually hand-operated, for turning screws with slotted heads. For screws with one straight diametral slot cut across the head, standard screwdrivers with flat blade tips and in a variety of sizes are used. Special screws with cross-shaped slots in their heads require a special screwdriver with a blade tip that fits the slots.