After upgrading from 7.34 to 7.36, my homepage now reads: "403 - Forbidden Error Common reasons for this error are:
Incorrect file/directory permissions: Below 644. In order files to be read by the webserver, their permissions have to be equal or above 644. You can update file permissions with a FTP client or through cPanel's File Manager.
Restrictive Apache directives inside .htaccess file. There are two Apache directives which can cause this error - 'Deny from' and 'Options -Indexes'."
I found "Directory index forbidden by Options directive" in error log and researched Drupal help blogs.
Then I changed permissions for settings.php as per one blog's recommendation, Website still will not load at all, even after permission given.
Don't understand Apache well enough to act on part 2 of original error screen advice about Restrictive Apache directives inside .htaccess file.