If all applications handle power state transitions gracefully, the user will perceive a more elegant and integrated system. When the computer is in the sleep state, the computer hardware, the system, and applications running on the computer must be capable of responding immediately to the power switch, communications events, and other actions. However, events in the system from both hardware devices and the real-time clock can be enabled to cause the system to exit the sleep state (that is, 'wake up') and quickly return to the working state. While in the sleep state, the computer's processor is not executing code and no work is being accomplished for the user. To the user, the system appears to be off.

The operating system will automatically enter the sleep state when the computer is idle or when the user presses a button to indicate that the current work session is over. The Windows operating system uses power-management hardware to put the computer into a low-power sleep state instead of shutting down completely, so that the system can quickly resume working.

It also ensures that all elements of the system-applications, devices, and user interface-can take advantage of the vast improvements in power management technology and capabilities. Windows power management makes computers instantly accessible to users at the touch of a button or key.

Windows power user tools