This is a picture of the pins used, but considering there is no reset on my dell, Im not sure what that thin wire connecting two of the pins is used for, any ideas anyone?
Ok the thin single wire is most probably black and is the Ground or Earth but I don't think I recall ever seeing a layout for FP set this way.
And from what you have shown in the diagram it is looped from the negative wire on the power switch.
So now we know the top pin for the power switch is the positive and the bottom is the negative.
Pre built machines like DELL and HP can be notorious for this, making a standard PC case swap annoying..
I have had an issue with a customers PC pre made where one pin needs to be earthed or the Audio would not be recognized as connected on start up.
I think it was also the same for the USB.
The work around was to connect a wire from the pin to the chassis of the PC to get the motherboard to recognize it's earthed since it would be pretty much impossible to jam a wire into the negative of the power switch plug.
Possible solution A:-
So you will have to find a wire with a single pin connector and strip the earthing end to make connection with the chassis of the motherboard if the earth is needed for the power switch to function.
Possible Solution B:-
It maybe necessary to loop a wire from the negative to the earth, in which you will have to find some way to loop the wire from the negative connection for the power switch to function which will be a nuisance.
EDIT:-
I see I am late and you have it all worked out by tracing the old one.
It is most likely this motherboard does not have a reset switch function available.
I have noticed some motherboards by the likes of HP, ACER and DELL to have certain functions unavailable or even removed.
I think it may have been an ACER which was actually an ECS motherboard with the PCI-E slot removed, possibly due to a fault with the original ones made so ACER buys them cheap to fit into their machines.
Just like HP buying defective seagate drives with the bad sectors blocked off to fit into thier machines.