component error - Joomla! Forum - community, help and support

i keep receiving error when choose "view site" (back-end)

404 - component not found
you may not able visit page because of:

an out-of-date bookmark/favourite
a search engine has out-of-date listing site
a mistyped address
you have no access page
the requested resource not found.
an error has occurred while processing request.
please try 1 of following pages:

home page
if difficulties persist, please contact system administrator of site , report error below..

component not found

the system administrator has said try disabling sef? how do this?

please bare in mind totally beginner @ this.

to disable sef:

1. log backend of website.
2. under "site" in top menu, click "global configuration.
3. under "site" tab, on right hand side under "seo settings", set any/all of these settings "no".
4. click "save , close"
5. give backend link try again, , see if works.