Custom PC black screen

I just finished building my own pc, and got everything to run…
GeForce 7600 GT
Asus p5n32-sli-se-deluxe
520 W power source
2 Gigabyte Ram

everything runs, the fans, the dvd drive…
but, i don’t get any video signal at all
there are no beeps when i start up, and i have tried removing the video card to see if it will beep, but to no avail.
in addition, the hard drive makes clicking noises when the pc starts up.
i cannot check BIOS because there isn’t any onboard gpu. is it a motherboard problem?
thanks