php login s MD5

<?php
include('includes/config.php');
$logusername = $_POST['username'];
$logpassword = $_POST['password'];
$database=mysql_select_db("databaze", $mysql);
if (isset($_POST['submit'])) {
$acc_dump = mysql_query("SELECT * FROM account WHERE username = '$logusername'")or die(mysql_error()); 
while ($acc = MySQL_Fetch_Array($acc_dump)){
$acc['username'] = $user; 
$acc['password'] = $pass;
}
$logpassword = md5($logpassword);
if (isset($logusername) && isset($logpassword)) {
    
    if (($logusername == $user) && ($logpassword == $pass)) {    
        
        if (isset($_POST['rememberme'])) {
            /* Set cookie to last 1 year */
            setcookie('username', $logusername, time()+60*60*24*365, '?go=admin', 'www.ww.ww'');
            setcookie('password', $logpassword, time()+60*60*24*365, '?go=admin', 'www.ww.ww'');
        
        } else {
            /* Cookie expires when browser closes */
            setcookie('username', $logusername, false, '?go=admin', 'www.ww.ww');
            setcookie('password', $logpassword, false, '?go=admin', 'www.ww.ww'');
        }
        header('Location: index.php');
        
    } else {
        echo 'Username/Password Invalid';
    }
    
} else {
    echo 'You must supply a username and password.';
}
} else {
?>
<form method="post" action="">
   Username: <input type="text" name="username"><br>
   Password: <input type="password" name="password"><br>
   Remember Me: <input type="checkbox" name="rememberme" value="1"><br>
   <input type="submit" name="submit" value="Login!">
  </form>
<?php
}
?>