hello, I have recently buy a motherboard AOD790GX/128M (socket AM2, mem: DDR2)
I have installed CPU, memory, plug the screen, one hdd, the alim and the "front switches" I push the power button and then.... the fans turn, the power ledturn on, the hdd led also... and stay in this state.
I have first think that one of my componant avec broken so I have try anothe CPU fan
I have try FOUR CPUs:
1x AMD ADO3800IAASCU (an old one possibly defaillant)
I have try with different memory sticks:
Transcend 502631-1971 (1Gb DDR2-800 DIMM 5-5-5)
grobill D2/25664667OT (2Gb DD2-667 PC5300)
I have try two alim boxs:
2x Advance ATX-5014 480W

By looking closely, the HDD does not start (but start if the IDE cord is unplugged), the alim have only a 4pins processor power connector but it is said in the documentation that the motherboard supports either 4-pins or 8-pins cpu power connector (I have also try with an alim that have a 8-pin connector)

I have try several combinaisons of thiese hard ware (even with an additionnal GPU in case of the onboard one is faillure) but in all case... the screen remain black and nothing more than lighting the led and fan turning.
what Have I done wrong? or is the motherboard defaillant?

please help me!!!