Hi, thanks for your attention.
I had already moved index.php to the root folder and changed
require(‘./wp-blog-header.php’); to
require(‘./blog/wp-blog-header.php’);
As you said, since stuff in ‘blog .htaccess’ should be copied to ‘root .htaccess’, I did so. Now root .htaccess includes rules as below,
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /blog/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /blog/index.php [L]
</IfModule>
# END WordPress
But still the problem remains………
Is there anything else I can do?