(redirected) Dell Inspiron E1705 will not power up. ..

Ok I have a Dell insprion e1705, I would turn my computer on and at first it would stay on for about 5 min then it would blue screen then I would turn it off. When I tried to turn it back on, you wouldn't hear anything power on but you would see the power light come on for a few seconds then it would go off.  If I left it alone for a few days it would boot up but again for about 5 min and then it would blue screen.

So I figured after I had tried the removing the battery and power and holding the power button down for 10 seconds, it was the motherboard....so I replaced the motherboard and I am having the exact same issue (except it doesn't boot up at all), when i hit the power button, you don't hear anything trying to power up and the power light will stay on for a few seconds then go off. I have replace my power cord, tried different wall plugs and I am out of ideas....any suggestions??