I just completed a new build using an ASUS M5A99X EVO motherboard. When I first attempted to start up the system all I got was a steady green LED on the motherboard -- no other LEDs, no beeps, no fans spinning, no video display. I removed all of the components and wires attached to the motherboard one at a time, and attempted to start the system after each item was removed. I got the same result each time -- just the steady green light.
I am down to just the power supply connection now, but still get just the green light. I have tested the power supply on another system and it works fine. Is it possible that the power supply (an ULTRA 750W ATX) is not adequate? Am I missing something else?
Unfortunately, I cannot return the motherboard because the warranty has expired and the upc code has been removed from the box.
I have the same motherboard, and also have the same problem. I was able to test the power supply by using the Paperclip test of green to black and then my power supply EchoStar 680Watt fires up, but as soon as I try to connect the 24 pin power supply connecter to motherboard. It does not work. I noticed that I when I try and connect a 4 pin power connecter to my EPU, the power supply fan will still turn on. If I use the 6 pin connector it will not. This board has an 8 pin EPU.