Blue square not showing oh screen

edit

Hello folk. I just started using opencv--python.

Intially I typed in some code found here.

link text

But when I typed in the code to my windows 7 64 bit computer and ran it. After a few syntax errors and typos on my part it ran just fine. I dectected the web camera that I have plugged in and it displayed the cameras video in a window. But I do not get that blue square that says it has detected my face. I am using a celron 2200 mhz with 2gb of ram so its not the fastest computer . Is it just that my computer is slow or is there something wrong with the code?

Ok here is the code. It was in the youtube video on the link that I posted,

import numpy as np
import cv2

#some comment i a foreign language which I cannot understand. I will put it
#thru Altavista later
face_cascade = cv2.CascadeClassifier('haarscascade_frontalface_default.xml')

video_capture = cv2.VideoCapture(0)

while True:
    ret, frame = video_capture.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    #capture test with image.
    #img = cv2.imread("wyld2.jpg")
   # gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)  

    faces = face_cascade.detectMultiScale(gray,1.3,5)
    for(x,y,w,h) in faces:
        cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)  

    cv2.imshow('video', frame)
    #some more foreign comments
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
video_capture.release()
cv2.destroyAllWindows()