Login Problems

// Connect to server and select databse.
 mysql_connect("$host", "$username", "$password")or die("cannot connect");
 mysql_select_db("$db_name")or die("cannot select DB");


// username and password sent from form
 $username=$_POST['username'];
 $password=$_POST['password'];


// To protect MySQL injection
 $username = stripslashes($username);
 $password = stripslashes($password);
 $username = mysql_real_escape_string($username);
 $password = mysql_real_escape_string($password);

$sql="SELECT * FROM $tbl_name WHERE username='$username' and password='$password'";
 $result=mysql_query($sql);


// Mysql_num_row is counting table row
 $count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){

// Register $myusername, $mypassword and redirect to file "login_success.php"
 session_register("username");
 session_register("password");
 header("location:login.007?action=success");
 }
 else {
 echo "
<html>
<head>
<link rel=\"stylesheet\" href=\"style.css\" type=\"text/css\">
<title>Login Failure</title>
</head>
<body>
<div id=\"container\">
<div class=\"content\">
<h1 class=\"title\">Login Failed</h1>
<p class=\"txt\">Incorrect Username/Password combination. If I were you I'd <a href=\"login.007?action=login\">go back</a> and try again.</p>
</div>
</div>
</body>
</html>
";
 }
}
if ($action == "success") {
 session_start();
 if(!session_is_registered(myusername)){
 header("location:main_login.php");
 }

echo "
<html>
<head>
<link rel=\"stylesheet\" href=\"style.css\" type=\"text/css\">
<title>Login Success</title>
<meta http-equiv=\"refresh\" content=\"2;url=index.007\">
</head>
<body>
<div id=\"container\">
<div class=\"content\">
<h1 class=\"title\">Login Success</h1>
<p class=\"txt\">You have been logged in and will be redirected to the main page.</p>
</div>
</div>
</body>
</html>
";
}
if ($action == "logout") {
 session_start();
 session_destroy();
echo "
<html>
<head>
<link rel=\"stylesheet\" href=\"style.css\" type=\"text/css\">
<title>Logout Success</title>
<meta http-equiv=\"refresh\" content=\"2;url=index.007\">
</head>
<body>
<div id=\"container\">
<div class=\"content\">
<h1 class=\"title\">Logout Success</h1>
<p class=\"txt\">You have been logged out successfully and will be redirected to the main page now.</p>
</div>
</div>
</body>
</html>
";
}
if ($action == "login") {
echo "
<html>
<head>
<link rel=\"stylesheet\" href=\"style.css\" type=\"text/css\">
<title>Login</title>
</head>
<body>
<div id=\"container\">
<div class=\"content\">
<h1 class=\"title\">Login</h1>
<p class=\"txt\">Please enter your information below.</p>
<form name=\"loginform\" method=\"post\" action=\"login.007?action=logincheck\">
<input name=\"username\" type=\"text\" id=\"username\" value=\"Username\" onfocus=\"this.value = '';\"><br>
<input type=\"text\" id=\"fakepassword\" value=\"Password\" onfocus=\"this.style.display = 'none'; document.getElementById('password').style.display = 'inline'; document.getElementById('password').focus();\">
<input type=\"password\" id=\"password\" name=\"password\" style=\"display: none;\"><br>
<input type=\"submit\" value=\"Login\">
</form>
</div>
</div>
</body>
</html>
";
}