I would suggest you to take the motherboard out of the chassis, place it on a non-conductive surface like a newspaper, a magazine or something similar, leave only motherboard, power supply, processor and Heat Sink/fan. Remove all the rest of components (no video card no memory)
Then clear the CMOS removing the CMOS battery and all power cables from the power supply to the motherboard, leaving the system without power for 20 minutes at least
After the 20 minutes reconnect the 2x12 and 2x2 and the aux power cables (if required by the video card). Power up the system using the onboard power switch and check if the system beeps. If it beeps it means that the system is posting
Thanks Diego_Intel, but still won´t power up, i did way you said the i plug the 2X12 pin and the 2X2, but as sun as i plugged the power
cord to the power supply ant turn on the PS, the led inmediatly turns on so i can´t power up the system. So taking a wild guess, do i have to look for a new mobo or a new PS??
Some of the first things you should check when you have a no post or no display issue on Intel Desktop Boards, is to check if the led light (most of the times green) on the motherboard is on and that the processor's fan spins.
If the led light is not on, there might be no power at all (however this does not indicate that the power supply is fully functional). If there is led acitvity, but not fan activity, the system is not powering up. You may try to power up the system using the onboard power switch (on some motherboards), using another power switch or making a short on the pins 6 and 8 (the red colored pins) on the front panel header (http://www.intel.com/support/motherboards/desktop/sb/CS-009016.htm)
This should be done with the system out of the chassis, as I said and only using, motherboard, power supply, processor and fan/Heat Sink, this would be to isolate the issue to a few components, having less hardware, mens, less variables, less hardware to swap. The system should beep 3 times that way since there is no memory installed (if we have fan and led activity).
If there is no fan/led nor beep activity, you should swap the power supply, the processor or motherboard would be the second option. (or you may test those devices on a known working and compatible system)
I hope this helps