Epox ep-8npa sli user manual barcode label says 5a 000901821. d33221 is also stamped on board

I don't have access to a motherboard manual, (User Manual), for the Epox EP-8NPA SLI motherboard, Wayne. Sorry.
The only info I have is the basic info on the Specifications,

http://www.newegg.com/product/product.aspx?Item=N82E16813123257

If this problem is in direct relation to the Front Panel header on the motherboard, it shouldn't be too hard for you to find the Power On switch connections.

(Plastic front of computer is the Front Panel.
Area of pins on the motherboard, that the wires from the Front Panel connect to, is the Front Panel header. { FP_1 )

Processor to the top, Ram Memory to the right, and the long white PCI slots to the bottom; the Front Panel header is the long black rectangular block of pins, at the very bottom right.

Pins go across the Top row, and across the Bottom row, of this rectangular block of pins.
Connections made will be from a pin on the top row, to a pin on the bottom row.

It only takes two contact pins for the Power On switch.
(The Power On switch is an ATX power on switch. It is located inside the plastic Power On button assembly.
Here is a basic example of an ATX power on switch,

http://www.directron.com/atxswitch.html )

Touch two pins (One top row, one bottom row), with an LED light.
Take the two wires of the LED light, and use them to touch the two contact pins.

Contact made is no longer than 2 seconds.

If you find the right two contact pins, the Power Supply should turn on.
If not, no harm, no foul.

For example, you have touched the two pins for the HarDDrive activity LED light.
Or pins for the Power On LED light.
You won't hurt anything using a small LED light for a jumper.

Once you find which contact pins turn the Power Supply on, therefore turning the computer on, you can experiment, and see what the other pins are for.

A) Power On LED light
B) HarDDrive activity LED light. and so on.

{ IF, the Power Supply does Not turn on, you have a bad Power Supply}

If this is not the problem simply state so in a Comment. We'll go on to see if we can find the solution.

Regards,
joecoolvette