The password function is case sensitive. If you originally set up your password while the CAPS lock was on, you will need to turn it on again when entering your password. Be very careful that you are entering your password in the correct case. You may want to change your password to all lowercase. If it still doesn't work, you must take out the main and backup batteries to initialize the HP 95LX. You will lose all your data, but the HP 95LX can be used again.