In Reply To:
I think the pest solution to make email field and Q/A field are required.
and thin whin the user want to requist his password he requist it in way that admin schoos at that time .
i think in this way admin can change the method of giving password at any time and both can work normaly . and i think it is very easy to any programmer to make Q/A fiels as required fields . but i am sure this programmer Not Dellow

.
Oh! Thats very very easy. Just go to the edit tables of your database manager and change the property of those fields as "Not empty!". So if the form does not submit those required values than it will give the respective error.
You do not need any extra programming. So if you do not understand, ask me again and I can give you step by step instructions.
However, what I have described about my problem is that I am not even able to change it as most of the users did already have those fields empty and I just cannot create and write answers for them which they do not know about it. Hence the problem.
What I did was I made the email address + user name as "UNIQUE" in the property field. Do this. This is helpful if you plan to have only one email address per user. And also set the other field for pass Q/A also as not empty field. (NULL/ NOT NULL). Do not set any defaults for that field. Otherwise it does not work.
However, incase if you are planning to go live than DO THIS BEFORE the terror.