You're trying to use a proprietary part on a different computer.
The plug connector you have was made for a 8(?) contact pin plug connector. (Usually 1 pin is missing, for a 'Key' pin)
The Front Panel header on the mobo you're trying to use it on, has a 10-pin Front Panel header. (Again, 1 pin missing for a Key pin)
You need to separate those individual connectors.
Yeah, I know.
This involves trying to slice/saw them out, and there's Nothing dangerous about that! (Sarcasm)
The connectors in that female plug are female metal terminal connectors. Individual connectors. Example,http://www.mcmelectronics.com/product/28-9420&utm_medium=Affiliate&ref=cj&utm_campaign=CommissionJunction&utm_source=CommissionJunction
The opening in the front, of course goes over the contact pin, in the Front Panel header on the motherboard.
The back of the connector, shown at the top; is crimped around the insulation of the wire.
The barrel shaped connector slides down into the individual socket hole, in the plug connector.
Looking at the Molex connector, observe the two 'Tangs' that stick out on either side. -> /
When the Molex connector is inserted into the plug connector's socket hole, the Tangs press against the sides of the connector.
When the Molex connector is at the correct depth, in the plug connector socket hole, the Tangs 'pop' out.
They pop out in small depressions, in the sides of the socket hole.
See how they angle towards the back?
If you slide the correct diameter of needle, down in the Front of the plug connector, (And in socket hole), you can depress one tang at a time.
Slides into the socket hole, right next to the Molex connector, and pushes down on the Tang.
Once depressed by the needle, lift up on THAT side a little.
Keeps the tang in a correct position.
Then insert the needle on the other side, and depress that Tang.
You can now remove wire and connector.
Takes a little practice on the first one. Second one goes a little faster, then you're on your way. Just sounds difficult explained so detailed.
With the individual wires, and their connectors; you can plug each wire in where you want. Connect to the contact pin in the Front Panel header, that you wish.
Trying to cut that connector apart, and leave individual amounts of plug for insulation; may prove unfruitful.
Most of the time the material in-between two of those Molex connectors, is very thin.
Maybe one connector will come away with enough material, maybe not. Most will not.
Also you risk slicing your fingers.
Or you could find a plug connector that fits that group of 7-pins, and transpose the wires over to it.
The front of your computer is the Front Panel.
The area of contact pins on the motherboard, that the Main wires connect to, is the Front Panel header.
Main wires being;
Power On switch wires
Power On LED light wires
HarDDrive activity LED light wires
Reset switch wires, IF used
Since you have the manual, out of curiosity are pins 2 and 4 Power On LED?
1 and 3 are HarDDrive activity LED?
5 and 7 are Reset switch?
For additional questions please post back in Comment.