You cannot match QUERY_STRING using Redirect
directive. Use mod_rewrite
instead like this in your root .htaccess file:
RewriteEngine On
RewriteCond %{QUERY_STRING} ^id=100$
RewriteRule ^index\.php$ http://www.domain.com/newhello? [L,R=301]
RewriteCond %{HTTP_HOST} ^(www.)?domain\.com$
RewriteCond %{REQUEST_URI} !/newroot/
RewriteRule (.*) /newroot/$1 [L]