Rob, Rob, Rob.............if I told you a thousand times, I............
Oh.......... where was I?
1) Power cables from Power Supply to motherboard:http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01237538&tmp_task=prodinfoCategory&cc=us&dlc=en&lc=en&product=3878557
A) 24-pin ATX main power cable;
Looking at the motherboard view the Right side. To the right of the Blue 39-pin IDE connector, is the 24-pin ATX main power cable connector, on the motherboard.
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
The power cable connector has a Lock on one side, and the motherboard connector has a matching Lock Tab.
When the power cable is deemed to be installed Correctly, and Properly; the Lock's hooked end is over the Lock Tab.
[Note* Color of connectors does NOT matter ]
B) 4-pin ATX +12 Volt power cable;
The processor socket is white in color. Around it is the black mounting ring.
The 4-pin ATX +12 Volt power cable connector on the motherboard, is to the Left/Bottom corner, of that black mounting ring.
Square, whitish (Opaque), and 4 socket holes.
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
2) Peripheral power cables from Power Supply;
A) The Harddrive is a SATA unit. Uses a SATA power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#sata
B) The optical drive/s (CD/DVD drive) are also SATA units. They use a SATA power cable.
A SATA power cable's connector has 15 contact pins. Between it, and the SATA data cable, it has the longer connector.
Peripheral Data Cables;
This is a general example of a SATA data cable, it's connector, and a SATA connector on the motherboard,
(Note* Color does NOT matter),http://en.wikipedia.org/wiki/File:SATA_ports.jpg
Here you can see the L-shaped opening of the connector, and matching L-shaped tab on the motherboard connector.
Most SATA power cable connectors, and SATA data cable connectors, have a lock. All you see is a 'bulb' type affair on top of the connector, that you squeeze down with a thumb tip.
Depress to remove, depress to install.
A 90 degree elbow connector for the SATA data cable, is used on the Harddrive, and optical drive. The straight connector end of the cable, plugs into the motherboard.
There are two SATA connectors on the motherboard. One White, one Black. One of them should have a SATA1 next to it.
(Or one will at least have SATA2 next to it)
SATA 1 connector is for the Harddrive. SATA 2 connector is for the optical drive.
The beauty of SATA is though, you can connect any SATA device, to any SATA connector on the motherboard; and BIOS will find it.
So it really doesn't matter what you plugged in where, as far as those two SATA headers are concerned.
3) Processor Fan cable, System Fan cable (Computer case fan);
Going back to the HP Support page above, and Motherboard Specifications; scroll down the list.
Click on the + sign to the left of the blue - Motherboard layout
Below the ATX12V1 connector is the System Fan connector.
This is where the computer case fan connects.
(ATX12V1 connector, is the 4-pin ATX +12 Volt power cable, connector)
Above the Ram Memory slots, and a little to the right; is the Processor Fan connector. Power to the fan. (CPU_FAN)
4) Front Panel audio connector, optical drive audio connector, Front Panel USB connectors;
Bottom edge of motherboard, from Left to Right;
Yellow connector is AUDIO1. Front Panel audio.
White connector is ATX_IN
For the audio cable from the optical drive.
Black connector (HD_AUDIO) is also for the Front Panel audio.
Don't know how they have the Front Panel audio, hooked up.
YOU will. The cable connectors to them are different from each other.
Front Panel USB connectors;
Further to the right are two white connectors. EACH one can support TWO USB ports.
One should be for the two USB ports in the Front Panel.
The other will go to a Card Reader in the Front Panel.
All the way to the right corner is the Front Panel header.
This is where the main wires from the Front Panel go.
Power On switch, Power On LED (light), and Harddrive activity LED (light)
The cable, and connector should match that 9-pin header.
If not here is an HP 9-pin Front Panel header - pinout,http://h30434.www3.hp.com/t5/Desktop-Hardware/Getting-a-new-case-i-need-Front-Panel-pinout/td-p/842897
Scroll down to the photo, and pinout. (Dave G)
Believe that is it.
For additional questions, or to have me clarify anything I have stated above, please post in a Comment.
(Ya know I was jus kiddin' above, right?..............