I have a super micro H88DCE-0 motherboard. I have a 2x AMD dual core Opteron 275 940 processor, Silverstone SST-ST75ZF PSU, BFG tech geforce 7800 GTX OC PCI express graphics card, 2X SATA hard drives, and 4x 1G corsair sdram ddr 400 ram, installed in a Thermaltake kandalf va9oooswa chassis. The system shows no video at all and I cannot even see the bio’s screen even if it is running correctly. The led on the back of the PSU lights up as well as the led on the motherboard. All the fan’s run and lights on the outside of the case illumines. I have downloaded the user’s manual and have run through the set up at least a dozen times. I have connected and reconnected all of the led’s coming from the chassis and other components. I tried clearing the CMOS as well. I looked for all the need jumpers, cables, and processors. As far as I can tell nothing as been damaged and I been taking great care in handling all hardware. The Graphic’s card is completely seated, processor are installed according to the user manual, the ram is set up on CPU 1 with cards in slots 1a and 1b the CPU 2 ram is set up the same. I have no other accessory cards or other devices hooked up. I pulled the motherboard from the case and verified the CPU’s were seated correctly, reheatsinked the fans, reconnected everything and still no go. Thinking it could be a possibly dead CMOS battery or just at bad board. I have two graphic cards and tried both of them in the top PCI slot. With this card, it is recommended I should boot up with only one card installed. The board powers up and only gives on one long beep with AMI BIO's, and all fans starts up other then that nothing else is happening. Pulled CMOS battery, reset CMOS again, still no go, put RAM in every configuration possible. When system loads with no graphic's card in place I still only get one long beep. I also tried connecting 3 different monitor's and 3 different graphic's cards. Two pci express X 16 and pci.

I am about out of ideas so any help would be greatly helpful.

If these are all new parts you might consider returning the motherboard for a new one.