DI - 524 dynamic PPOe DSL password problem

OK im trying to connect my adsl to my router , it gives dynamic IP adress so i chose that option when i put my user , the password filed is allready filled in , and when i try to put new password and press aply it says no change , and router cant log in try the modem to the ISP. Ok i have this problem for few months before that it work good , ive tryed new firmware but same stuff . ?? any idea ? o and even when i put some random password it has same answer when i press save it says NO CHANGE . !! is it hardware problem ?