OK, are you referring to your Maintainence light or your check engine light?

If it's your maintainence light, this is what you do;

Turn the car off, completely off. then press and hold the trip button. While doing that, turn the car to the on position but don't start the car. Hold the button for 10 seconds and the light should go out. After it goes out, turn the car off then start the car and you're all set.
That light is just a service reminder, that's all...nothing more.

If it's the Check engine light this is what you do
Go to Autozone and have them pull the code for you
then Click here for the problem