HP part number 5188-5473 brings up the Asus A8N-LA motherboard, made especially for HP,http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=us&docname=c00647121#N413
The rest of the number/letters do me no good.
I will elate some information based on the above, and see if it does you any good;
1) The Asus A8N-LA has connectors for two types of Harddrives;
A) IDE. Also known as PATA.
This type of Harddrive uses a flat ribbon IDE(PATA) data cable,http://en.wikipedia.org/wiki/File:Nappe.svg
(The Asus name probably won't be on it. These two IDE data cables just happen to be made by Asus )
The connectors on each end have 40 socket holes. One socket hole will be blocked off. (Or should be) ONLY 39 socket holes are used.http://en.wikipedia.org/wiki/File:PATA-cable.jpg
A look at the connector on the motherboard;http://en.wikipedia.org/wiki/File:ATA_on_mainboard.jpg
Looking at the motherboard illustration, look at the Bottom/Right corner. There are two IDE connectors. They are marked as IDE 1, and IDE 2.
Scrolling down a little bit to the motherboard photo, you will see IDE 1 connector is Black in color, and IDE 2 is Blue in color.
The IDE (PATA) harddrive's data cable goes to IDE 1.
Optical drive/s (CD/DVD drive) goes to IDE 2.
This is the type of power cable from the Power Supply, that goes to an IDE (PATA) harddrive,http://www.playtool.com/pages/psuconnectors/connectors.html#peripheral
There is usually a square, or rectangle, or two bumps; used on the IDE ribbon cable connector, to line up with the connector on the motherboard, or harddrive, or optical drive.
It is called a Locating Lug.http://en.wikipedia.org/wiki/File:PATA-cable.jpg
This particular IDE data cable connector, has two raised bumps, for a Locating Lug.
It lines up with a Cutout in the motherboard's connector, or the harddrive's connector, or the optical drive's connector.
IF, there is NO Locating Lug, use the faint Red stripe on the side of the IDE data cable.
The red stripe is on the same side as Number 1 wire.
Number 1 wire goes to number 1 pin.
On a harddrive, or optical drive, number 1 pin is ALWAYS closest to the power cable connection,http://www.playtool.com/pages/psuconnectors/connectors.html#peripheral
Looking at the photo number 1 pin is on the Right side. It is closest to where the 4-pin Peripheral power cable plugs in.
Looking at the motherboard photo, the Yellow, and Blue, and Black, and White connectors; to the left of the Blue IDE connector, and Black IDE connector; are SATA connectors.
SATA 1 is Black. This is where the SATA harddrive's data cable, is supposed to plug in.
The BEAUTY of SATA though, is that you can plug the harddrive into ANY of those SATA connectors on the motherboard, and BIOS will find the harddrive. (Or any other peripheral device)
An example of a SATA data cable, and it's connector,http://en.wikipedia.org/wiki/File:SATA_ports.jpg
The red SATA connector shown below the SATA cable example, is just a different style of SATA motherboard connector; than what your motherboard uses.
Note the L-shaped opening in the SATA data cable's connector.
Lines up with the L shape on the motherboard connector, or harddrive connector, or optical drive connector.
Most SATA data cable connectors, also have a Lock on them.
Sometimes it's a Lock you can easily see.
Most times, it is a small depression you depress with your thumbnail, or a little 'bulb' you depress.
Depress/unlock to plug the cable in, or remove the cable.
The 90 degree angle connector end, (As shown), plugs into the harddrive, or optical drive. The Straight connector end plugs into the motherboard.
This is an example of a SATA power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#sata
Between it, and the SATA data cable connector, it is the larger of the two.
SATA power cable connector has 15-pins.
SATA data cable connector has 7-pins.
Also note the rectangular depression on the SATA power cable's connector. That is where you depress to unlock the connector.
The SATA power cable's connector also has an L-shaped opening.
2) IF, you are trying to hook up a laptop harddrive to this motherboard, you need to determine if the laptop harddrive is an IDE (PATA) type, or a SATA type.
There is a label on the laptop harddrive. It has the manufacturer code on it. Type the number/letters in your browser search bar, and click on the search icon. (Magnifying Glass)
Now purchase an external enclosure.
The external enclosure opens up, and the laptop harddrive goes inside, and plugs into an interface.
Close the external enclosure, and plug it's USB cable into any available, open USB port on your computer.
It will be a 2.5 external enclosure.
Harddrive's are measured across their width.
A desktop harddrive is 3.5 inches across in width.
A laptop harddive is 2.5.
Example of a 2.5 IDE (PATA) external enclosure,http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1086960&CatId=2782
Example of a 2.5 SATA external enclosure,http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3195233&CatId=2783
For additional questions please post in a Comment.