How can I “reset” an Arduino board?

Question

I\'ve uploaded a sketch to an Arduino Uno whose loop is something like this:

void loop(){
    Serial.println(\"Hello, World!\");
}

So, now,

Answer 1

If the port says Already used, then you are probably using the wrong port.

Switch it to the port where you connected your Arduino and then try to re-upload, you will definitely see it work.