ISPConfig 2 - Login Issue

As I am a beginner don't flame me too much, I have never worked with any Linux based machines until very recently so yet I'm learning. I work for a company, I'm mainly specialized in web designing but however, they bought a dedicated server to host their websites. Everything was good but a couple of days ago they asked for a certain site which I implemented MySQL for (for better managment). The guy who had set up the server with the ISPConfig, didn't told me the password for MySQL so I had to change it. I managed to change it but now, I get this error when I try to login at http://mymachineip:81/
(I believe it's called the Administrator Panel). Here's the error that's thrown:

HTML:

Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'root'@'localhost' (using password: YES) in /home/admispconfig/ispconfig/lib/classes/ispconfig_db_mysql.lib.php on line 77

Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'root'@'localhost' (using password: YES) in /home/admispconfig/ispconfig/lib/classes/ispconfig_db_mysql.lib.php on line 77

Warning: Cannot modify header information - headers already sent by (output started at /home/admispconfig/ispconfig/lib/classes/ispconfig_db_mysql.lib.php:77) in /home/admispconfig/ispconfig/web/login/login.php on line 62

I've read your forums but as I am a beginner, I can't do it myself. I saw that I need to change the password elsewhere also (I've updated the MySQL table named sys_user with the query UPDATE sys_user SET "mypassword" WHERE username = "admin"). It worked but now I can't connect to that panel I used to connect fine. As far as I was concerned from the very beginning of the time that error was thrown, I knew that I had to change the password elsewhere to match the new MySQL pwd I've set through that query.

Now, I ask for your help because I'm really stuck and it's kinda urgent. Where and how I navigate to those other files that I must edit and update the MySQL password. I've saw that a lot of people suggested to navigate trough home/admispconfig/... but I have no idea where I can find this directory or how to edit that file.

Thanks, I appreciate a lot!

(This occured because I needed to install PHPMyAdmin to administrate the databases. PHPMyAdmin works fine, but that Admin Panel doesn't).

 

And how do I managed to go to that directory and change that password? I'm using PuTTY to SSH into the machine but I really have no idea how to navigate to that dir and change the pwd. Could you please point me in the right direction?

 

Till,
Thank you very much! I, like the orginal poster was handed legacy web server and just recently found it had ISPConfig installed. I was unable to login as no one had the password. After a couple of days of trying, I found this article and eureka, you gave me the answer. I'm now looking at the ISPConfig frontend. Now if I only knew what to do with it...