I have a 2010 Macbook pro. I replaced the logic board on the computer. When I go to power it on I hear the post sound the screen kinda flickers then the light on the front fades out and nothing. I can press the caps lock key and the light comes on and the fans are spinning so i know the machine is running but i get no display. When I go to turn it off I have to hold the power button for 10 seconds then it turns off. I tried resetting the pram and no change. Any Ideas?