Asus AP1720-E1 - Manual (Page 66)

3-4 Chapter 3: Powering up
3.3 Powering off the computer
You must first exit the operating system and shut down the system before
switching off the power. For ATX power supplies, you can press the ATX
power switch after exiting or shutting down the operating system.
The message “You can now safely turn off your computer” does not
appear when shutting down with an ATX power supply.
Using the dual function power switch
While the system is ON, pressing the power switch for less than 4 seconds
puts the system to sleep mode or to soft-off mode, depending on the BIOS
setting. Pressing the power switch for more than 4 seconds lets the
system enter the soft-off mode regardless of the BIOS setting. See section
“4.5 Power Menu” in Chapter 4.
Using the OS shut down function
If you use Windows 98SE/ME/2000/XP, click the Start button, click Shut
Down, then the OK button to shut down the computer. The power supply
should turn off after Windows shuts down.