[Pikami]

The error i'm having is :  Notice: Undefined index: hasStarted in C:\xampp\htdocs\test\random.php on line 3

Your problem is written in plain english "Undefined index: hasStarted in C:\xampp\htdocs\test\random.php on line 3"
You are trying to access the variable $_SESSION["hasStarted"] but is is not set.
You can check if a variable is set with the method isset()