Warning: require_once(/home/mywebsite/public_html/components/com_sef/joomsef.php) [function.require-once]: failed to open stream: No such file or directory in /home/mywebsite/public_html/plugins/content/joomsef/joomsef.php on line 15
Fatal error: require_once() [function.require]: Failed opening required '/home/chiang11/public_html/components/com_sef/joomsef.php' (include_path='.:/usr/lib/php:/usr/local/lib/php:/home/chiang11/php') in /home/chiang11/public_html/plugins/content/joomsef/joomsef.php on line 15

Is on the front end of my site, I cant install joomsef or unistall joomsef.
Its just full of errors and my site is totally screwed.

How can I just delete everything related to joomsef without having to login to backend because i cant do anything there.

Hi,

There was probably a problem with write permissions to some of your Joomla directories causing not all the required files to be installed.
Use FTP to delete the following files and directories:
/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

Then you should be able to log into the backend again. There go to Site -> System Information -> Directory Permissions and check that all the directories are writable before trying to install JoomSEF again.