The power LED connector is likely located on the red or the green connector prongs in the foreground.
If your computer doesn't have a light to tell you it is on, you can install one yourself with relative ease. All modern mainboards (i.e., motherboards) have a place for you to connect an LED to indicate the computer's on/off power status. A power status LED is a snappy, useful visual gauge of your computer's most basic condition.
Instructions
1. Purchase an LED from your local consumer electronics shop or from the Internet that is rated for use in computers. It should be 3.3 volts and have a socket that is compatible with mainboard connectors. Some mainboards have 2-pin connectors, while others have 3-pin connectors. Check out your mainboard to see which it has before you buy your LED.
2. Turn off and unplug the computer, then ground yourself prior to working with the hardware to remove static electricity.
3. Open the tower to gain access to the motherboard.
4. Plug the wire into the Power LED connector on your mainboard. This connector is clearly labeled (but usually in very small print) on the motherboard itself. It should say "Power LED," Pwr LED," or "PLED," and it will be located on the same part of the mainboard as the hard disk (i.e., "IDE") LED connector and the connector for the on/off switch on the front of the computer. It is usually located in one of the motherboard's corners. If you have trouble finding it, it should be diagrammed in the motherboard's user's manual.
Make sure you plug it in in the correct direction. LEDs are diodes (that's the "D" in "LED") and will only conduct electricity in one direction. If you put it on backwards, it won't work.
5. Close up the computer tower.
6. Mount the LED in the desired position on your computer tower. You will want it to be in a position where you can see it, but where it will not get in the way of drive bays or other interfaces with the computer tower.
Tags: computer tower, your computer, power status, your mainboard