System can't power up

[letmesearch]

I am tinkering with a computer system and I am encountering problems with powering up the system.

After pressing the power button, the system doesn't power up - the power supply doesn't even spin up.

After cracking open the case, I notice that the front panel connectors look weird.

XXXXO
XXXXX

X's are pins
O is a blank area.

Top area (XXXXO) says PLED and PWRBTN
Bottom area (XXXXX) says HDLED and RST.

My power LED connector is three pins wide, but has two wires (white and green)
My power SW connector is two pins wide and has two wires (red and white)

Since I have a 'blank' space, will that even work?

I can't review my current case (It's packed) and the motherboard manufacturer didn't give any information.

Also, anyone have any steps to also diagnose a power supply failure?

[PeterPen]

You can cut the 3pin power led into half. So you get one side is white and the other is green ( the middle pin is empty) and put the

Green (PLED)
| white (PLED)
| | power switch cable (doesn't matter which way )
| |||
| |||
XXXX
XXXXX
|| ||
|| Reset Cable (doesn't matter which way)
||
HD LED
(+ first )

Some motherboard has extra three pin for Power LED but they cheap one may not with.