registered users not receiving emails

Hello,

When a user registers by clicking on the “Register” button and entering a user name, password, password again and email address and then he clicks on “Register”, the page goes back to the same Register page (but blank). The user gets created in word press but the user does not get a notification email. Additionally, if the user tries to login with the credentials he entered when creating his account, it does not work, it simply takes him back to the login/register screen with no error messages. Also, if the users clicks on the forgot password link and enters his email address, it takes him to a “page cannot be displayed” page. Any help will be appreciated