You should get the BIOS splash screens on power up even if the HDD is dead. Without these I tend to question if it`s the monitor, power supply or your graphics card.
You could ensure you have power to the monitor or better still try it on another known PC. You could also re-seat your graphics card and ensure any extra power leads to it are connected correctly.
If it`s none of these, you may be looking at your motherboard or PSU.