is a tip to help save everyone time and energy. Rather than turning off your PC after every use, putting it in hibernate or standby mode will save just as much energy—using only 2.3 watts, which is essentially the same as if the computer is off. These modes also allow you to leave applications and documents open and pick up your work at a later time and ultimately help you save time by avoiding long start-up times. I would recommend hibernation rather than standby because it creates an image on your hard-drive of your current desktop and open applications so your work will still be there when you return. Stand-by is similar but it does not create an image, but rather turns off power to all peripherals except for the memory. Current applications should still be running when you bring the computer out of standby, but hibernation offers more security and reliability with the backup image.
Please visit Microsoft's overview page on PC hibernation and standby for more information.