A) With great tact and diplomacy;
Do not refer to a Personal Computer as a CPU.
CPU = Central Processing Unit.
Another term is Microprocessor, or simply Processor for short.
CPU = Processor
B) Because of the method you used to refer to the Computer, I do not know if you're talking about; the PROCESSOR did not start, or the Computer.
C) If I we are to believe this is a reference to the Computer;
1) Check the Power Supply voltages,
2) Substitute the Power Supply; with a KNOWN to be working, Compatible power supply, for a temporary test unit.
A) If ALL the LED lights were on at once, they would use less than 1 Watt of power.
B) EACH fan uses 2 to 3 Watts of power.
C) A typical Processor can use 51 to 125 Watts of power.
Just depends on what Processor it is.
A Power Supply with a weak voltage power rail, will not have enough power to turn the Processor on.
However I am still confused by the statements;
1) "CPU did not run"
Does this mean the COMPUTER did NOT turn on, which implies the Power Supply did not turn on;
Does this mean LED lights came on, fans may be spinning, but Windows does not load?
2) "I can't find any signal on my Computer........"
Signal = Voltage.
To see if there were voltages going through the motherboard, you wouldn't be posting on here. You would know how to take a multimeter, and test them.
Means to me you see No Signal on the monitor.
D) Are you FOLLOWING Anti-Static Procedures?
E) Power Supply voltages prove to be good, or you are using a KNOWN to be good, Compatible power supply?
Disconnect EVERYTHING from the motherboard.
NO cables to the motherboard, EXCEPT the 24-pin ATX main power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24
[NOTE* Color of connector does NOT matter ]
,and the 4-pin ATX +12 Volt power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#atx12v4
Disconnect the data cable AT THE motherboard, for the Harddrive, and optical drive/s. (CD/DVD drive)
Disconnect the power cables to them also.
Disconnect ANY USB front panel cables.
LEAVE processor fan wire connected to motherboard.
You want the Processor, finned Heatsink sitting on it, and the Processor fan.
ONE stick of Ram Memory in Slot 1. (DIMM 1)
Leave graphics card in, IF used; or monitor is connected to the VGA port on the motherboard. (D-Sub connector)
Turn the Power Supply on.
You should be able to bring the BIOS Setup screen up.
If no, consider the motherboard to be bad.http://www.msi.com/product/mb/G31M3-L-V2---G31M3-LS-V2.htmlhttp://www.newegg.com/Product/Product.aspx?Item=N82E16813130217
Post back in a Comment, as to the information I need.
CPU = Processor
PC = Computer, or just use Computer.