Try this first:
1. Try resetting the SMC by unplugging the power cord, waiting 15 seconds, plugging the cord back in, waiting 5 seconds, and then pressing the power button.
If this step doesn't work, then you really need to change the logic board.
Or, if you bought the computer with an American Express, they'll double your warranty up to 5 years. My Macbook Pro just gave up the ghost and they are taking care of it. Never hurts to try!