The CMOS password does not work

On a customer’s computer I repeatedly tried to set a password in the CMOS to lock the whole system. I can open the CMOS SETUP FACILITY, the PASSWORD SETTING and enter the password. This type give me the cice of the manager and user password. I may put in any pasword in either category and seva it to the CMOS, nothing happens, the computer ingonres it and starts normally. What do I do wrong or fail to do, any help is appreciated.