Driver - a computer program, through which the operating system gets access to the hardware device. In general, for the use of any device (both external and internal) need a driver. Usually operating sistemama comes with drivers for the key hardware components, without which the system will not work. However, for some devices (such as the graphics card or printer) may require special drivers that are usually provided by the manufacturer of your device.
GetWindowsDrivers (EN|RU)