Hi,
Check that the RAM is seated properly. Do this with the power disconnected.
Disconnect everything except the RAM and video card (unless it has onboard video) and power button connection i.e HDD, ODD, USB etc and see if you can get into BIOS
Is there a speaker connected to the appropriate motherboard header pins at all? This may help to give you a clue as to what is or is not happening i.e beep error codes.
What is the make and model number of the motherboard?