install with xampp

Xampp installs wherever you place it, and then its ‘\htdocs\’ folder is where you place your ‘wordpress’ folder (using whatever name). In my own case, that amounts to this:

H:\xampp\htdocs\wordpress\wp-config.php.

Then, here are my entries in wp-config:

define('WP_HOME','http://localhost/wordpress');
define('WP_SITEURL','http://localhost/wordpress');

define('DB_NAME', 'dbname');

define('DB_USER', 'root');

define('DB_PASSWORD', '');

$table_prefix='wp2_';

Are you going to your own equivalent of ‘http://localhost/wordpress’ and not finding your installation?

Here is the guide I had first used:

http://premium.wpmudev.org/blog/how-to-install-wordpress-locally-for-pcwindows-with-xampp/

define(‘WP_HOME’,’http://localhost/wordpress’);
define(‘WP_SITEURL’,’http://localhost/wordpress’);

do not find them or have not seen them …

That is fine, I believe.

What is your actual path and what URL are you using?

‘\xampp\htdocs\wordpress\’ = ‘\http://localhost/wordpress’

What do you actually have for each of those?

.. error in establishing a database connection … I have done something wrong in the database ?

No, you just have yet to tell WordPress how to find and access it, if it exists.