1) the power LED is on (12 volt for your CPU- its on your motherboard)
1.1) Make sure all cables are connected well
1.2) Please clear CMOS to have a try(refer to motherboard manual for details)
1.3) If there is still blank screen, please connect the connector of speaker to check if there is any beeps
1.4) Keep the necessary components ( a CPU, a memory, a graphic card )on board to test and remove the motherboard from the case to put on non conductive material, the box your motherboard came in is perfect.
1.4.1) If there is no post, please contact your retailer for a check
2) the power LED is off (12 volt for your CPU- its on the motherboard)
2.1) Make sure the power cable which connects to the front panel is well
2.2) Please swap a power supply for a try if possible.
2.3) If the problem still remains, please contact your retailer for a check