说明：  登陆密码，功能： 加载系统前用于检测用户密码，无口令不能登陆。若密码正确则进入系统加载目录 通过改写ＭＢＲ实现
(Login password function: loading system used to detect the user' s password, can not login password. If the password is correct by rewriting the MBR into the system load directory)