To accept payments by money order but not by check, please follow these steps:

1. Using an FTP client (eg. Filezilla), download a copy of ../catalog/includes/languages/english/modules/payment/moneyorder.php

2. Using a text editor (eg. Notepad), modify the 'MODULE_PAYMENT_MONEYORDER_TEXT_TITLE' definition

For example:

Before modification:

define('MODULE_PAYMENT_MONEYORDER_TEXT_TITLE', 'Check/Money Order');

After modification:
define('MODULE_PAYMENT_MONEYORDER_TEXT_TITLE', 'Money Order');

3. Save your changes
4. Upload the modified moneyorder.php file back to ../catalog/includes/languages/english/modules/payment/moneyorder.php using your FTP client (eg. Filezilla)

This document is FAQ573.