Serial1 not declared in this scope

Using Arduino Programming Questions
#1

I just moved from XP to Windows 7 and now my code, when I verify it, now says Serial1 is not declared in this scope.

void setup() {  
  // Initialize serial port 1:
  Serial1.begin(9600);
  delay(100);
  // Clear and turn backlight on:
  Serial1.write(12);
  Serial1.write(17);
  delay(5); // Required Delay
  Serial1.write(12);
  delay(5);
  Serial1.print("Test Subject");
  Serial1.write(13);
  Serial1.print("001");
  delay(100);
}

void loop() {
}
#2

What Arduino have you got selected? Serial1 only works on a Mega.

Rob

#3

Oh, I forgot to change it when I changed comps.

#4