Unless your computer is located within arm's reach, gaining access to the power button on the machine might not always be easy. In fact, if the computer is under a desk or table, shutting down or turning on the machine might actually be somewhat of a chore. However, there is a simple solution to the problem.
Most modern computers support powering on the computer with a PS/2 keyboard. Even when the power to a computer is off, there remains a small amount of electrical current in some of the circuits on the motherboard. For computers with an ACPI compliant BIOS (most are), a PS/2 keyboard can be used to power on the computer by simply pressing a key.
Shutdown the computer. Turn the computer back on and press the "Delete" or "F2" key as soon as you see the initial boot screen. The BIOS menu screen appears.
Enter the BIOS password if prompted to do so. Use the arrow keys on your keyboard to navigate to the "Advanced" or "Advanced Settings" menu option. Press the "Enter" key.
Move the cursor to the "Power Management" or "ACPI Management" option. Press the "Enter" key and then move the cursor to the "Wake on Keyboard" or "Power on by Keyboard" option.
Press the "+" or "-" key to change the "Wake on Keyboard" or "Power on by Keyboard" option value setting to "Enabled."
Press the "F10" key to save the BIOS setting changes and exit the utility. The computer will restart.
Press the power button on the computer and hold it for four or five seconds. The computer powers off.
Press any key on the keyboard. The computer should start without the need to push the power button.
Things You'll Need
PS/2 keyboard or USB keyboard with PS/2 adapter
ACPI compliant BIOS