1) The 9-pin header you are referring to, is the Front Panel header.
(Processor to the top, Ram Memory slots to the right, the Front Panel header is at the bottom right corner on the motherboard)http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00906129&lc=en&cc=de&dlc=&product=3397528
The plastic piece on the front of your computer is the Front Panel.
(Sometimes referred to as a Bezel)
Make a drawing, and notes as to where the individual wires go from that Front Panel header plug, (One-piece plug), to the Front Panel.
Follow the wires from the plug to the Front Panel.
Mark down where Each wire goes.
You may have to take components off of the Front Panel, in order to see exactly where Each wire goes.
You may have to remove the Power On button/switch assembly from the Front Panel.
It may have the Power On LED light, Power On button, (Switch), and perhaps the HarDDrive LED activity light, in this assembly.
The wires are color coded.
Generally, but not always, when two wires are used in conjunction with each other, (Example, Power On switch, or Power On LED light), the wires will be twisted together.
One wires insulation may be of a solid color, and the other wire may be white, with a stripe in the color of the solid wire.
Example: Wire with Red color, and wire twisted with it may be White, with a Red stripe.
See if these two wires go to the Power On switch.
End of example.
Follow each twisted pair of wires back down to the Front Panel header plug.
See which socket holes the individual wires go to.
Mark it down in your drawing, and notes.
Mark where the individual socket holes plug onto each pin, in that Front Panel header. (9-pin header)
When you are finished, you will have a pinout for the Front Panel header on the Asus M2N68-LA motherboard, and will know where the individual wires go from your ThermalTake V3 computer case.
For the LED lights there is a Positive pin, ( + ), and a Ground pin. (Power On LED, and Harddrive activity LED, for example)
(Ground. Also referred to as the Negative pin. ( - )
This is DC Voltage)
If you have the polarity backwards, (Positive wire of the LED light is going to the Ground pin, Ground wire of the LED light is going to the Positive pin), the LED light will be dim.
Switch the wires around.
If you have questions, or need clarification of what I have stated above, simply state in a Comment.
(Believe upper right of your page)