In many cases we do not know is a PHP error, or MySQL username password does not cause the CMS to run wrong, you can use the following code to test itThe method is simple: Save the following code as test.php and put it into the web directory to execute. Code as follows: <?php/** * Test PHP and MySQL connection * EDIT: www.jbxue.com * * * $link =mysql_connect ("localhost", "root", "123"); if (! $link) echo "faild! connection error, username password is incorrect"; else echo "ok! can connect"; ?> the parameters of the mysql_connect () function are: MySQL server name or IP, mysql user name, MySQL user password.