Getting Rid of the "Access denied for user ..." Error in PHP

This error usually looks like this :

Warning: mysql_query() [function.mysql-query]: Access denied for user 'ODBC'@'localhost' (using password: NO) in C:\xampp\htdocs\intra\process_mypage.php on line 382

Warning: mysql_query() [function.mysql-query]: A link to the server could not be established in C:\xampp\htdocs\intra\process_mypage.php on line 382

To get rid of this error, follow this step :

• Check your connection to the database
• Check server name, username and password
• Check whether the connection is opened or not, because the common mistake is that you forgot to open the connection :p