Open in two different windows.
The Top link is for a clear photo of the motherboard, and the letter designations.
The Bottom link is a navigation guide for those letter designations, HOWEVER they do NOT match up. I will guide you using both links.
1) Go to the Top link - Main View
Look at the right side for letter R.
This points to the 24-pin ATX main power cable's connector, on the motherboard.
In the second link - Hardware Details - it is letter
J- Main Power Connector
This is a general example of a 24-pin ATX main power cable, and it's respective connector on the motherboard,http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24
(NOTE* Color never matters)
Note that there is a Lock on the side (Middle), of this main power cable's connector.
There is also a matching Tab on the motherboard connector.
To remove this power cable the top of the Lock is squeezed in. This action brings the Lock's hooked end away from the Tab, on the motherboard connector.
The Lock operates like a see-saw on a playground.
2) Go towards the Top/Middle to the letter C, in the Main View.
This points to the 4-pin ATX +12 Volt power cable's connector, on the motherboard.
In the Hardware Details it is the letter C also.
C - Auxillary 12V ATX Connector
This is a general example of a 4-pin ATX +12 Volt power cable, and it's respective connector on the motherboard,http://www.playtool.com/pages/psuconnectors/connectors.html#atx12v4
Note that it has a Lock, and the motherboard connector has a Tab, also.
That's it for power cables TO the motherboard.
3) Since there is only one IDE (PATA) connector on the motherboard, I'm going to assume you are using a SATA harddrive.
Uses a SATA power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#sata
Note that a SATA power cable's connector has 15 contact pins.
Between it, and a SATA data cable's connector, the SATA power cable's connector is longer.
Note also the L shape inside the connector.
There is also a Lock tab you depress on the cable's connector, when unplugging it.
4) General example of a SATA data cable, and it's respective connector on a motherboard,http://en.wikipedia.org/wiki/File:SATA_ports.jpg
You can see the L shape a little better here. A SATA data cable has 7 contact pins.
The connector shape usually used on the Harddrive, is a 90 degree bent elbow.
The straight connector end is plugged into the motherboard's SATA connector.
In the Main View the letter U is the SATA connector designator.
Look to the left of the Front Panel connector, designated by the letter T.
Those four Orange connectors are SATA connectors.
The Harddrive usually plugs into SATA 1. In Hardware Details this is shown by the letter L.
L- SATA Connectors
Looking closely you can see the SATA 1 connector, is at the Bottom of the motherboard.
However the beauty of SATA is, that you can plug the harddrive into any of those SATA connectors, and BIOS will find it.
In the Main View the letter S on the right side, points to where a computer case fan plugs in.
The letter F in the middle, points to where the Processor (CPU) fan connects.
J is for the Front Audio Connector. (Audio ports on Front Panel of computer)
K is where a Card Reader would plug in.
This is the kind of power cable a Floppy Drive, and a Card Reader uses,http://www.playtool.com/pages/psuconnectors/connectors.html#floppy
L points to where the Firewire ports connect to.
(IEEE 1394 Connector)
The letter O points to where the Front Panel USB ports connect to.
Going back to the letter T - Front panel Connector, in the Main View.
Go to Hardware Details, and click on -
M - Front Panel connector
4 pins on the Left side, 5 pins on the Right side.
The pins on the Left side are numbered EVEN.
The pins on the Right side are numbered ODD.
Starting at the BOTTOM on the Left side, going towards the Top;
Pins 2, 4, 6, and 8. No Pin 10.
Starting at the Bottom on the Right side, going towards the Top;
Pins 1, 3, 5, 7, and 9.
A) Pins 1 and 3 are for the HarDDrive activity LED. (Light)
Pin 1 is for the Positive ( + ) wire.
If the HDD LED is dim when the harddrive is active, switch the wires around.
B) Pins 5 and 7 are for a Reset switch, IF a Reset switch is used.
C) Pin 9 is N/C.
Not Connected. 5 Volt test for the factory
D) Pins 2 and 4 are for the Power On LED. (Light)
Pin 2 is for the Positive ( + ) wire. If the PWR LED is dim when the computer is on, switch the wires around.
E) Pins 6 and 8 are for the Power On switch.
For additional questions please post in a Comment.