Intel Motherboard DP45SG start problem(one short beep sound)

hi i have a problem and i really need help...
i just assembly a new desktop with :

Motherboard: Intel Extreme DP45SG
RAM: Kingston KVR1333D3N9/2G DDR3 1333 with 1.5 V
CPU:Intel Quad Core 2.83 GHz
Graphic Card: ATI Radeon 4870x2
320 GB HDD Seagate
1000W Power Supply Tagan SuperRock II

Yesterday I connect it to a monitor to check it. I plug the power supply and push the switch. All fans started to and aftes a few seconds (5-7 seconds) one short beep sounded from the motherboard and stay there with nothing shown in the screen or an anyother beep. I change the posiion or RAM and Graphic Card in motherboard but the same ...just one short beep sound...

what does one beep meens in this intel motherboard? does it pass POST or there is a problem with the RAM Or Graphic Card..
i searched the internet and i could not find any specific solution...

Pls help!!!

yes i connect both of them..i also put another graphic card to check and the pc boot normally..so it should be something with the card....is the power supply not enough ..it's a tagan 1000 watt

One short beep indicates a good POST. One thing to keep in mind is that the POST checks only the interface to the video card. It cannot test the inner workings. THat is what the Mark One Eyeball is for.

I would check both the monitor and the video card with another computer.