Recover xampp directory from old HD

[MarkHoward]

I first created the databse in MySql.
Then I imported a backup.sql file.
I could see the tables and their content through phpMyAdmin.

Then I renamed the installed htdocs to htdocs_orig.
Then I copied the old htdocs onto the new place as htdocs.

Using the XAMPP control panel I can start apache and MySql
But then two strange things happen:
1. when I click apache Admin, a php file click.php opens.
2. when I click on MySql Admin it is asking me for a username and password

I'm very confused about which username and password it is asking about. It doesn't seem to be either the root password that I set up in the apache>security section OR the database username and password from the old system.

Now, even when I restore htdocs_orig as htdocs, I still can't get access.

How far back do I have to go to try this again - and be sure that I haven't got any old usernames and passwords stored anywhere?