If it's just black then BIOS is reading VGA out through the motherboard, and something else is the problem (even BIOS itself, which usually fails if there is a ground fault or component failure)
If you still have no luck, start removing devices from the system until you get a response. Remove peripherals one by one, and power cycle it each time, in this order:
USB devices except keyboard
NICs and modems
Sound cards
Other IDE/PCI cards
IDE drives
SCSI drives
RAM, DIMM by DIMM
Keyboard
Video card
At some point you should at least get a POST fault in the form of a beep. If you don't, the board is dead.