I ran into this today actually. In my case I had the RS and Enable lines crossed. Triple check your LCD -> 'duino connections: RS, Enable, and Contrast are close to each other on both, but are in different orders. I found it easier on my board to fix it in software
Oh, and even if the LCD is wired wrong or not even powered, the 'duino's LED(s) should light up if its powered.
Good luck.