Our module Aricie - SimpleSignin allows you to set simple registration form by selecting desired fields (lastname, firstname, email, username, password, ...) but il requires DotNetNuke 4.8.1 or later. You only have to put it on a registration page and config it.

Thanks for that but My client will not pay extra amount for these paid modules so

    WANT A SOLUTION WITHIN THE DNN CORE MODULE .

 a) i Remove the display name feature by adding [FIRSTNAME LASTNAME ] in display property of Admin>>UserSetting

b) already make requiresUniqueEmail="true"  in web.config

But  Still cant find a way to make emailID as UserName

Can Anybody is there who can help me plz ????????????????????????????????????????????????????????