What's missing now is a call to Serial.begin() in setup() and calls to Serial.print() in loop(), to show when you are changing the state of the pins. If you write out that you are setting the pin low, but the light doesn't go off, then there is a hardware problem. If the statement that you are writing the pin low never appears in the serial monitor, then you have a software problem (or a hardware problem). But, lets figure out which is which, first.