HI i have done a questionnaire and when they submit i want the page to say thank you ... i can get it to do that but cant stop it from showing the rest of the form

i am trying to get the form to dissappear after they have submitted their responces???

PHP Code:
// check to see if the user has submitted the form
if( isset( $_POST['course'] ) ) {

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<title>Feedback Form</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">

<body><form name="BasicForm" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">

My name is Fizlar and I am currently studying for my Masters degree in Information 
Systems at the University of Sheffield, England. This questionnaire is part of 
my on-going research to try to gain a comprehensive understanding of the problems 
that users like yourself experience when querying a database.<br>
<form method="post">
<p>Can You Please type your age </p>
  <input name="AGE" type="text" value="AGE" size="10">
<p>What is your first language if not English</p>
 <textarea name="LANG" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>


    <textarea name="QUES1" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
    <textarea name="QUES2" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
    <input type="radio" name="rating1" value="1">
    1 Very Helpful<br />
    <input type="radio" name="rating1" value="2">
    2 Helpful<br />
    <input type="radio" name="rating1" value="3">
    3 Uudecided<br />
    <input type="radio" name="rating1" value="4">
    4 Unhelpful<br />
    <input type="radio" name="rating1" value="5">
    5 Very Unhelpful<br />
    TO <br>
    YOUR NEEDS?</p>
    <input type="radio" name="rating2" value="1">
    1 Very Satisfactory<br />
    <input type="radio" name="rating2" value="2">
    2 Satisfactory<br />
    <input type="radio" name="rating2" value="3">
    3 Undecided<br />
    <input type="radio" name="rating2" value="4">
    4 Unsatisfactory<br />
    <input type="radio" name="rating2" value="5">
    5 Very Unsatisfactory
    <textarea name="QUES5" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
  <br />
    <input type="radio" name="rating3" value="1">
    1 Very Useful<br />
    <input type="radio" name="rating3" value="2">
    2 Useful<br />
    <input type="radio" name="rating3" value="3">
    3 Undecided<br />
    <input type="radio" name="rating3" value="4">
    4 Unhelpful<br />
    <input type="radio" name="rating3" value="5">
    5 Very Unhelpful<br />
    YOU REQUIRED? </p>
    <input type="radio" name="rating4" value="1">
    1 Yes<br />
    <input type="radio" name="rating4" value="2">
    2 No <br />
    <input type="radio" name="rating4" value="3">
    3 Undecided <br />
    WERE YOU <br>
    <input type="radio" name="rating5" value="3">
    1 Yes<br />
    <input type="radio" name="rating5" value="2">
    2 No<br />
    <input type="radio" name="rating5" value="1">
    3 Undecided<br />
    TO USE? 
    <textarea name="QUES9" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
    <input type="radio" name="rating6" value="1">
    1 Very Useful<br />
    <input type="radio" name="rating6" value="2">
    2 Useful<br />
    <input type="radio" name="rating6" value="3">
    3 Undecided<br />
    <input type="radio" name="rating6" value="4">
    4 Unhelpful<br />
    <input type="radio" name="rating6" value="5">
    5 Very Unhelpful</p>
    REQUIRED? </p>
    <input type="radio" name="rating7" value="1">
    1 Very Helpful<br />
    <input type="radio" name="rating7" value="2">
    2 Useful<br />
    <input type="radio" name="rating7" value="3">
    3 Undecided<br />
    <input type="radio" name="rating7" value="4">
    4 Unhelpful<br />
    <input type="radio" name="rating7" value="5">
    5 Very Unhelpful</p>
    <input type="radio" name="rating8" value="1">
    1 Yes<br />
    <input type="radio" name="rating8" value="2">
    2 No<br />
    <input type="radio" name="rating8" value="3">
    3 Undecided<br />
  <p>Q13, IF NOWHY NOT? </p>
    <textarea name="QUES13" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
    <br />
    <textarea name="QUES14" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
    DID THIS<br>
    <input type="radio" name="rating9" value="1">
    1 Very Useful<br />
    <input type="radio" name="rating9" value="2">
    2 Useful<br />
    <input type="radio" name="rating9" value="3">
    3 Undecided<br />
    <input type="radio" name="rating9" value="4">
    4 Unhelpful<br />
    <input type="radio" name="rating9" value="5">
    5 Very Unhelpful</p>
    <textarea name="QUES16" cols="60" rows="3" wrap="virtual">TYPE IN HERE</textarea>
    <input type="radio" name="rating10" value="1">
    1 Very Poor<br />
    <input type="radio" name="rating10" value="2">
    2 Poor<br />
    <input type="radio" name="rating10" value="3">
    3 Undecided<br />
    <input type="radio" name="rating10" value="4">
    4 Good<br />
    <input type="radio" name="rating10" value="5">
    5 Excellentl</p>
    <input type="submit" name="course" value="Submit">
  $R1 = $_REQUEST['rating1']; 
  $R2 = $_REQUEST['rating2']; 
  $R3 = $_REQUEST['rating3']; 
  $R4 = $_REQUEST['rating4']; 
  $R5 = $_REQUEST['rating5']; 
  $R6 = $_REQUEST['rating6']; 
  $R7 = $_REQUEST['rating7']; 
  $R8 = $_REQUEST['rating8']; 
  $R9 = $_REQUEST['rating9']; 
  $R10 = $_REQUEST['rating10']; 
  $Tx1 = $_REQUEST['QUES1'];
  $Tx2 = $_REQUEST['QUES2'];
  $Tx3 = $_REQUEST['QUES5'];
  $Tx4 = $_REQUEST['QUES9'];
  $Tx5 = $_REQUEST['QUES13'];
  $Tx6 = $_REQUEST['QUES14'];
  $Tx7 = $_REQUEST['QUES16'];  
  $age = $_REQUEST['AGE'];
  $lang = $_REQUEST['LANG'];

$sql = "INSERT INTO QUESTION (Num_id, Age, LANG, Question1, Question2, Question3, Question4, Question5, Question6, Question7, Question8, Question9, Question10, Question11, Question12, Question13, Question14, Question15, Question16, Question17) VALUES (NULL,'$age','$lang','$Tx1','$Tx2','$R1','$R2','$Tx3','$R3','$R4','$R5','$Tx4','$R6','$R7','$R8','$Tx5','$Tx6','$R9','$Tx7','$R10')"; 

$user = "****";
$pass = "***** ";
$db = "***";
$link = mysql_connect( "localhost", $user, $pass );
if (! $link)
    die ("could not connect to MySQL");
mysql_select_db ($db)
    or die ("could not connect to $db: ".mysql_error() );

$result = mysql_query ($sql);