No power to the motherboard?
Have you performed the test to see whether the problem is the Power On switch, or the Power Supply?
The test involves bypassing the Power On switch.
Nothing to do with the actual cable (Wires) that go from the motherboard to the Power On switch.
If you bypass, and the Power Supply comes on, you have a bad Power On switch.
If you bypass, and the Power Supply does Not come on, you have a bad Power Supply.
The MSI (Micro Star International) K8MM-V motherboard uses a 20-pin ATX main power cable.http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain20
The Green wire you see is the Soft Power On wire. (PS_ON)
ANY Black wire you see is a Ground wire.
A jumper wire is used to make a Momentary contact from the Green wire, to ANY Black wire.
Observe the photo to the far Right.
Where the wires go down into that connector is the Back of the connector.
Each socket hole has a wire.
At the end of every wire is a metal terminal.
The metal terminals are pretty far down in the socket holes.
The jumper wire must go down into the socket hole, NEXT to the wire already in there, and Must touch the metal terminal.
The jumper wire slides down in the socket next to the wire, and touches the metal terminal down in the bottom, of the socket hole.
A paper clip is usually used for a jumper wire. The small diameter of the paper clip allows it to slide next to the wire, go down in the socket hole, and touch the metal terminal at the end of the wire.
A paper clip is straightened out, then bent into a U shape. The legs go down in the socket holes, (Green wire, and ANY Black wire)
The middle of the paper clip is wrapped few times with Black plastic electrical tape.
This is for your finger, and thumb to hold onto.
The contact period is no more than 2 seconds. (1001,..1002)
The voltage you will be dealing with is 5 Volts DC.
Two D cell flashlight batteries produce 3 Volts DC.
Computer plugged into power, computer case open, computer laying on it's side.
Use the jumper wire.
If the Power Supply comes on, you have a bad Power On switch.
If it doesn't, you have a bad Power Supply.
The Power On switch is located inside the plastic Power On button assembly.
This is one generic ATX power on switch that I have found fits many computers,http://www.directron.com/atxswitch.html
Should like to know your findings.