If you prefer to stop your computer running but not turn the power off, click the arrow to the right of the Shut Down button and, in the resulting shortcut menu, choose Hibernate on a laptop (or simply close the lid of your laptop) to shut the computer down. If you want to reboot (turn off and turn back on) your computer, choose Restart.
If you’re going away for a while but don’t want to go through the whole booting up sequence complete with Windows 7 music when you return, you don’t have to turn off your computer. Just click the Sleep command instead to put your computer into a kind of sleeping state where the screen goes black and the fan shuts down.
When you get back, just click your mouse button or press Enter or, in some cases (especially on some laptops), press the Power button. Your computer springs to life, and whatever programs and documents you had open are still open.If your computer freezes up for some reason, you can turn it off in a couple of ways. Press Ctrl+Alt+Delete twice in a row or press the power button on your CPU and hold it until the computer shuts down.
Don’t simply turn off your computer at the power source unless you have to because of a computer dysfunction. Windows may not start up properly the next time you turn it on if you don’t follow the proper shut down procedure.