WARNING_PLUGIN_NOT_INSTALLED: /home/****public_html/administrator/components/com_sef/plugin/
Error loading component: com_sef, 1
Error building Admin Menus

tried to uninstall but admin now down and frontend no longer working

what happened - can i uninstal manually if so which files do i delete

/administrator/components/com_sef
/components/com_sef
/libraries/joomla/installer/adapters/sef_ext.php
/libraries/joomla/updater/adapters/sef_update.php
/plugins/content/joomsef
/plugins/extension/joomsefinstall
/plugins/system/joomsef
/plugins/system/joomsefgoogle
/plugins/system/joomseflang

deleted the above files as per other posting but still no good