bronfai wrote:$ cfg ['Servers'] [$ i] ['auth_type'] = 'http';
$ cfg ['Servers'] [$ i] ['user'] = 'root';
$ cfg ['Servers'] [$ i] ['password'] = 'MYPASSWORD';
You have a wrong understanding, how these credentials are working. You only need to specify user and password, when you choose "config" as auth_type. In that case, phpmyadmin will try to login automatically by using these values for the MySQL Login. If you specify "http" or "cookie" (i prefer "cookie" by the way, it looks nicer), you will be prompted instead for a User and Password, the values of config.inc.php then will be ignored (the do not have any meaning, you even may leave them empty).
bronfai wrote:When I log on phpMyAdmin, in the authentication window I write
User name: root
Problem: "Wrong username / password. Access denied."
In Xampp Control Panel "MySQL STOPPED" is always shown and I can not start (Apache and ProFTPD are running)
How I can solve?
I think, that you may already have another MySQL installation up and running, which collides with Xampps MySQL. You cannot run MySQL twice. Login as root and run a "ps -fe" command in order to find out, if there is already a process called "mysqld". Also if you simply enter "mysql ...." in a shell and there is starting up the MySQL interpreter, this might not be the Xampp interpreter (which is stored in /opt/lampp/....), but the interpreter from your Linux distribution. You can find out that by entering "which mysql" in a shell, it tells you exactly, where mysql is stored. i think, it is /usr/bin/mysql.
If i am right, you have to start your Application manager or Software manager (or similar, depends on your distribution) and de-install the MySQL version. Then reboot the machine and try to start Xampps MySQL again. Keep in mind, that Xampps MySQL comes with a user "root" without any password (you may change that later on in PhpMyAdmin, there is a User menu).