LED stays on until arduino is unplugged

/*
 * Manvi Mittal
 * Version 1
 * Leaning digital imputs
 */

const int pinLed = 7;
const int pinButton = 2;
int readValue = 0;

void setup()
{
  // put your setup code here, to run once:
  pinMode (pinButton, INPUT);
  pinMode (pinLed, OUTPUT);

  Serial.begin (9600);

  digitalWrite (pinLed, HIGH);
  delay (50);
  digitalWrite (pinLed, LOW);

}

void loop()
{
  // put your main code here, to run repeatedly:
  readValue = digitalRead (pinButton);

  if(readValue == 1)
  {
    digitalWrite (pinLed, HIGH);
  }

}