Q:

MacbookPro5,3 (mid-2009) won't boot elementary OS

I have a MacbookPro5,3 (C2D 2.66, 64 bits EFI, 8GB RAM, nVidia 9400m & 9600m GT) and I am unable to boot into elementary OS. 
I have tried both with Apple's boot manager and rEFInd to no avail.  I am able to select the USB drive where my Freya image is and then select either Try elementary OS or Install elementary OS. 
In all cases, the blinking "e" logo shows, blinks 3-4 times, then the LCD's brightness turns to the maximum and everything hangs.  I waited and waited, nothing happens, I have to reset the laptop. 
What am I missing?  Why can't I boot elementary? 

A:

I have exactly the same laptop and I had the same problem. 
Press e on the selected option, after quiet add nomodeset and press F10 to save changes and boot. 
Keep in mind that after installing Freya, the first time you boot, you 'll have the same problem.  You need to install nvidia drivers (Applications > Additional Drivers) and everything will work fine afterwards.