overheated burned smell, no power at all

I have a D600 that won't power up. It does nothing at all, no lights no nothing, even when I plug it in no lights or anything. I sniffed inside of the fan area and  it smells like somthing burned. I took the laptop apart to see if anything looked burned but everything looks fine. Is there a way to test the motherboard, could it be burned out? Or maybe the power supply, which i cannot identify. Any help or suggestions would be nice!