When it comes to turning off and shutting down, Windows Vista isn’t like earlier versions of Windows. In Windows Vista, turning off a computer and shutting down a computer are completely different operations. Turning off a computer doesn’t power it down; only shutting down the computer powers it down completely.
By default, when you turn off a computer running Windows Vista, the computer enters the sleep state. When entering the sleep state, the operating system:
Automatically saves all work.
Turns off the display.
Puts the computer in sleep mode.
In sleep mode, the computer’s fan stops, the computer’s hard disks stop, and the computer enters a low-power consumption mode in which the state of the computer is maintained in the computer’s memory. The next time you turn on the computer, the computer’s state will be exactly as it was when you turned off the computer.
Because the operating system saves your work, you don’t need to save documents and exit programs before turning off the computer. Because the computer is in a low-power consumption state, the computer uses very little energy. For mobile computers, the sleep state will use very little battery power. If, while in the sleep state, the mobile computer’s battery runs low on power, the state of the computer is saved to the hard disk and then the computer is shut down completely—this state is similar to the hibernate state used in Windows XP.
You can turn off a computer and make it enter the sleep state by following these steps:
Click the Start button.
Click the Power button.
To wake the computer from the sleep state, you can do either of the following:
Press the power button on the computer’s case.
Press a key on the computer’s keyboard.
You can turn off and turn on mobile computers by closing or opening their lid. When you close the lid, the laptop enters the sleep state. When you open the lid, the laptop wakes up from the sleep state.
Regardless of whether you are using a desktop computer or a mobile computer, the way the Power button works depends on the system hardware, the system state, and the system configuration:
If the computer hardware doesn’t support the sleep state, the computer can’t use the sleep state, and turning off the computer powers it down completely.
If the computer has updates installed that require a restart or you’ve installed programs that require a restart, the computer can’t use the sleep state, and turning off the computer powers it down completely.
If you or an administrator has reconfigured the power options on the computer and set the Power button to the Shut Down action, the computer can’t use the sleep state, and turning off the computer powers it down completely. See Chapter 7, “Working with Laptops and Tablet PCs,” for more details on configuring power options.
To help differentiate between turning off and shutting down a computer, Windows Vista displays two different views for the Power button:
An amber Power button, depicting a shield with a line through the top of it, indicates that the computer will turn off and enter the low-power sleep state.
A red Power button, depicting a shield with a line through the middle of it, indicates that the computer will shut down and completely power off.
Because the computer is still drawing power in the sleep state, you should never install hardware inside the computer or connect devices to the computer when it is in the sleep state. The only exception is for external devices that use USB or IEEE 1394 (FireWire) ports. You can connect USB and FireWire devices without shutting down the computer.
As mentioned earlier, turning off a computer running Windows Vista puts the computer in a low-power sleep state instead of completely powering down the computer. To completely power down the computer, you must shut it down. Shutting down the computer ensures that the power to the computer is turned off.
Because of possible confusion regarding the sleep state and the power-down state, be sure to unplug a computer running Windows Vista before installing or connecting devices. To shut down a computer running Windows Vista, use one of the following techniques:
Click Start, click the Options button to the right of the Power and Lock buttons, and then click Shut Down.
Press Ctrl+Alt+Del. The red (Shut Down) Power button should be displayed in the lower-right corner of the window. Click the Power button.
Do not install hardware inside a computer running Windows Vista or connect non-USB/non-FireWire devices without first ensuring that the computer is completely powered down. If the computer’s Power button is red and shows a shield with a line through the middle of it, the Power button shuts the computer off and completely powers it down. If the computer’s Power button is amber and shows a shield with a line through the top of it, the Power button turns off the computer and puts it in the low-power sleep state.
To shut down and then restart a computer running Windows Visa, you can use either of the following techniques:
Click Start, click the Options button to the right of the Power and Lock buttons, and then click Restart.
Press Ctrl+Alt+Del. Click the Options button to the right of the Power button, and then click Restart.
A restart is sometimes required to complete the installation of programs and automatic updates. A restart might also be required to finalize a system configuration change.