Black screen problem - help please!

Hi all,

I'm having issues with graphics cards. Either I'm an idiot, or something is seriously wrong.

I have an Intel P4 3.2 Ghz processor on a DX38BT motherboard with 2.0 GB of DDR3. It has a 700 watt power supply. I tried using a Geforce 8800 GT in all of the sockets (both PCIE 2.0's and the PCIE x16), yet didn't get any display (black screen) on boot. It doesn't sound as if it's POSTing, either (no beeps). I swapped out this card for a Radeon HD 3870, and got the same results... Normally, I'd think it's the mobo at this point, but here's the kicker: I tried both of these cards on another LGA 775 mobo and got the same results! When I put in an old ATI card in the AGP slot on the old mobo, it worked fine!

Does anyone have any thoughts on why this might be happening? Because I'm about two steps away from shipping all of the merchandise back >

And, yes, I've connected all of the power to both the motherboard and the cards. The fans on the cards spin up fine.

thanks!!

-Max

Wow.... Yep, color me stupid... Thanks for pointing out what should've been the obvious. This is what I get for just reading that it was an LGA 775 board, and not looking closer

Thanks!