Oh wow that is an older motherboard ...support for Intel Core 2 eh? One thing you could check is that the CPU you are using is on the support list for that motherboard. I am a bit of an AMD fanboy but I do recall that the support for Intel CPUs is shorter than AMD so you have to be sure the exact CPU is on the list published by the motherboard manufacturer.
Other things to check is to be sure the PSU is hooked up to the 24 pin and the multi pin near the CPU (Usually 4 or 8 pins). If your graphics card requires power check that it is getting it too. Make sure the monitor is connected to the graphics card, not the motherboard. FInd the input select button on your monitor and press that until you get the correct input (if it is on the wrong one). So many things can cause this condition. You didn't say..but I assume you have fans and lights just no monitor? A BIOS speaker hooked up would also help here if your machine is in a POST beep state. RAM seated all the way in? Try just one stick?
Do you get some beeps at the beginning? Does it load anything (that you could tell without actually looking at the screen) Do what Kshipper said, it's good advice. It could be your RAM, try it with just one stick of RAM and move it around the slots.