Chapter 1: The Basics of Windows XP
Suspending Windows XP Some computers have a Suspend Mode, Hibernate Mode, or Standby Mode in which the computer remains on, but the disk drives, fan, and screen turn off. If your computer has such a mode, a Stand By option appears on the Turn Off Computer dialog box. To switch your computer to Suspend Mode, choose Start | Turn Off Computer and click Stand By.
To wake up a computer that has partially powered itself down, press the SHIFT key a few times.