I can't support you about my work personally.

If you can't understand how to use this hack, I recommend you to restore same as original.

copy these files from the original core package into your system.

user.php
modules/system/blocks/system_blocks.php
modules/system/templates/system_userform.html
modules/system/templates/blocks/system_block_login.html
include/common.php
include/checklogin.php
language/english/global.php