Thank you Twitch for your reply, but I found the problem.

For other people's reference, here is how i found the problem:

In the Admin, under Tools I used the "developers toolkit" to search for the old password in all the .php files, and there I found a file 'configure.php' in the main includes file. This is a different file than the one that is found in the renamed-admin-folder.

Just changed the db password on that file and now it works fine. So for future reference to other searchers, there are 2 different configure.php files that need to be updated when the db password changes. One is in the main includes folder, the other is in the includes sub folder inside the renamed-admin-folder.

Good luck to all.