Very pecuiliar mobo malfunction

[simplyalex]

ok so i have an asus m4n78 pro mobo, i bought it as a barebone. i got everything plugged in right and such in the case and the mobo wouldnt power on. i thought i grounded it so i took it out of the case and put it on some cardboard and tried to run it there, with the same result. i remained optimistic and unplugged the harddrive and she was running! now knowing it was the hardrive, i tried a different sata hardrive that i knew worked and an ide harddrive, still with no response. my problem is it only works without a harddrive plugged in.... is it a defective mobo or am i doing something wrong? pls help ~alex

 

[r_manic]

Can you try using a different SATA cable? You may also want to look into your PSU; maybe it's not providing enough power to drive your components.