How to remove the index.php string as part of every URL

At the Moment I use Joomla 3.4.x / CB 2.0.10. In order to remove the 'index.php' string as part of each URL I did the following:

1. in den Global configuration (back end):
- set 'Use URL rewriting' to YES
- set 'Search Engine Friendly URL's'to YES

2. Because I use the security tool: 'Admin tools' there were already 2 file called .htaccess and .htaccess.admintools....because of this I renamed the original htaccess.txt to old_htaccess.txt


...but there was no improvement ?!?... (PS: I got these advises via Internet reserach)

That's a general Joomla support question, which we do not provide here. Please post to Joomla.org forums or review the Joomla documentation below regarding SEO. You need to use URL rewriting (requires mod_rewrite) with htaccess.

docs.joomla.org/Seo

docs.joomla.org/Enabling_Search_Engine_Friendly_(SEF)_URLs

Joomla provides its htaccess file as htaccess.txt in Joomla root. I've no idea how this behaves with Admin Tools as we didn't develop Admin Tools.