Hi, my brother is having a problem with his unibody MacBook that he bought just a few months ago. It won't start when the power button is pressed, the sleep indicator light turns on and that's all. There's no start up tune, and nothing appears on screen. I had a similar problem with my MacBook Pro. I was told that the logic board needed to be replaced due to too much dust or moisture. Could this be the same problem? and has anyone else here ever had the same problem?