Macbook Pro won't power up My Macbook Pro will not boot normally or in safe mode. My power cable lights up green when it is connected. Pressing the power button does nothing. However, if I unplug the battery and wait a few seconds, the screen will light up, the apple and the progress/status bar comes on, as well. The working indicator starts to whirl but when the status indicator gets about a tenth across the bar, the screen goes black. There is no hard drive sounds.
I have had the same problem with my mac book pro. Maybe you could try booting from an external HDD?
In my case I tried everything from replacing the hard drive, reset PRam(hold cmd+shift+p+r right after pressing the power button), replacing the internal battery; all without success. So if none of those things won't work it's probably your motherboard having a serious issue. Only thing I could have done was replacing it.