1. Change the password in the includes/configure.php file
2. Change the password in the admin/include/configure.php file.
Do check whether other details like the server name, website URL etc. are also set correctly.
Even though you might have kept your folders in a folder which makes the domain name as:
the following values still should be just your site name:
The following values should be as (including the trailing slash):
And make sure you don't overwrite any one of the configure.php file with the other. Although they both have the same filename they are different and server different purpose.