Registration & login Help

[lavarock09]

Hey All...

I have these two pieces of codem login.php & reg.php

reg.php

<?
include 'config.php';
$conn = mysql_connect($host,$username,$password);
mysql_select_db($db) or die("Unable to select database"); 
$username2 = ($_POST[username]);
$password2 = ($_POST[password]);
$password3 = md5($password2);
   $password3 = md5(substr($password2, 18, 51) . md5(substr($password2, 2, 14)));
   $password4 = md5(substr($password3, 12,23) . md5(substr($password3,1, 64)));
   $password5 = md5(substr($password4, 15, 21) . md5(substr($password4, 23, 34)));
   $password6 = md5(substr($password5, 3, 5) . md5(substr($password5, 32, 64)));
   $password7 = md5(substr($password6, 17, 34) . md5(substr($password6, 32, 34)));
if (mysql_query("INSERT INTO `users` (`username`, `password`) VALUES ('$username2' , '$password7')"))
{
echo ("Registration Unsuccessful"); //Yes I know these (the two echoes, one to the left and one below) Are the wrong way round
}
else
{
echo ("Registration Successful. You may now login with your username and password."); 
}
?>

login.php

<? 
include 'config.php'; 
$conn = mysql_connect($host,$username,$password); 
mysql_select_db($db) or die("Unable to select database, Please Check you config.php file. If this is correct, ask your web administrator"); 
$username2 = ($_POST['username']); 
$password2 = ($_POST['password']); 
$password3 = md5($password2); 
   $password3 = md5(substr($password2, 18, 51) . md5(substr($password2, 2, 14))); 
   $password4 = md5(substr($password3, 12,23) . md5(substr($password3,1, 64))); 
   $password5 = md5(substr($password4, 15, 21) . md5(substr($password4, 23, 34))); 
   $password6 = md5(substr($password5, 3, 5) . md5(substr($password5, 32, 64))); 
   $password7 = md5(substr($password6, 17, 34) . md5(substr($password6, 32, 34))); 
$row = mysql_query("SELECT * FROM `users` WHERE `username` = '$username2'"); 
if ($row['password'] == $password7) 
{ 
echo ("Successfully Logged in"); 
} 
else 
{ 
echo ("Username or Password incorrect...Please try again."); 
} 
?>

reg.php will put the heavily encrypted password into the db...but when I come to login with login.php it won't match the password

Can anyone help?