To Turn off Windows 95/98/ME/XP/Vista/7 computers, click on Start, Shut Down, and choose Shut Down and click OK.
For Windows 8, you'll need to move your cursor to the bottom right corner of the screen to bring up the Charms menu. You can also bring up the Charms bar by pressing the Windows key + C on your keyboard. Then click on Settings (gear icon) , Power, and finally Shut Down.
Although it may take longer to shut down your system the right way, it will save you a lot of grief. Many computer issues can be avoided by properly turning off your computer. Because of the way computers work, its also best to shut down and restart your computer every few days even if you leave it on 24 hours a day.