Magento – Display Address Fields on Create an Account

By default Magento doesnt show the address fields within “Create an Account”. To make the sign up process more user friendly you can enable the address fields by adding the following:
Simple way to show that is to add the below code in customer.xml or in local.xml

        <reference name="customer_form_register">
            <action method="setShowAddressFields"><value>true</value></action>
Source : 

Customer cannot login to magento

Using the free theme sometime may result  of customer not logged in problem issue. To resolve this issue we need to put the for key field in the login form.
In app/design/frontend/default/…/template/persistent/customer/form/login.phtml , around line 41 should look like

 <form action="<?php echo $this->getPostActionUrl() ?>" method="post" id="login-form">
 <?php echo $this->getBlockHtml('formkey'); ?> 

If the code is not seen then add it then customer login works