Take all the add-in cards out of the board (anything in pci/pci-e slots). Also, take the memory out. Try to turn it on again. Motherboards will always beep, or flash or something if memory is not detected (check your MB documentation). If the motherboard does not do this, the motherboard is at fault. If it does beep, slowly add things (starting with the memory) until the computer stops working. When you find the problem component, try plugging that component into a different slot, if available, just to make sure the slot on the MB isn't bad.
I work in a computer repair shop and this is what I would do.
I'm making the assumption that the power supply is good (because you said you tested more than one) and that it is plugged in properly.
IM still not sure what it could be .. i did all that it came out like it is the motherboard... but then , ive built my older pc back together , plugged it in and the same thing happened , no picture and everything running up ..
Ok thank you for trying to help.. i went to do diagnostics and it turned out that the graphics card had to be plugged in differently in this motherboard with the power supply... YaY .. my baby is back.