Motherboard: ASUS P4SD Motherboard Specificationshttp://h10025.www1.hp.com/ewfrf/wc/document?docname=c00022505&lc=en&cc=us&dlc=en#c00022505_doc
Board Form Factor: uATX
uATX stands for Micro-ATX,http://en.wikipedia.org/wiki/MicroATXhttp://en.wikipedia.org/wiki/Computer_form_factorhttp://en.wikipedia.org/wiki/Computer_form_factor#Tabular_information
HOWEVER, the Power Supply is an ATX form factor,http://www.911forpcs.com/hp-media-center-power-supply.html
,of a sort.
Form Factor related directly to desktop computer Motherboards.
Now has 'evolved' to relate to the computer case, and Power Supply.
When referring to a Power Supply, and the ATX form factor; you are not only referring to the size, and shape of the Power Supply's case; but also the type of power cables used, and the technology used within.
Size and shape of an ATX power supply is approximately;
6 Inches Wide, 5.5 Inches Long, and 3.5 Inches in Height.
(152.39mm Wide, 139.69mm Long, and 88.89mm in Height)
Power cables included with Power Supply's nowadays, will include all the power cables you'll need, with probably some left over.
HOWEVER, looking at the 'ATX' form factor designated for your computer, to wit from the ad above, it does NOT fit the above size, and shape.
More like 6 Inches Wide, 4 Inches Long, and 3.5 Inches in Height.
Looks like they just crammed everything into one small box.
Remove motherboard, and all internal hardware, into a new computer case?
Most Mid-Tower to Full Tower size computer cases, will have a Support Plate that accommodates a Micro-ATX form factor motherboard, OR an ATX form factor motherboard.
Just look at the Support Plate mounting holes.
Ones for a Micro-ATX (uATX) motherboard, will have uATX next to them, or MATX, or mATX.
Ones for an ATX motherboard, will have ATX next to them.
However check the computer case manufacturer info to be sure.
[ The motherboard mounts to a Support Plate.
The Support Plate can be an integral part of the metal frame, of the computer case; or a separate metal plate that attaches to the computer case metal frame ]
Not what you had in mind Joel? Post back in a Comment.