I assume this happened:
You happily installed LAMPP, checked if everything was OK, which it was.
Then you changed your passwords, suddenly, MySQL has a Deactivated status!
Check this file: "/lampp/htdocs/xampp/mysql.php"
You need to change this line:
(or something similar to that line)
Save the file, check the status again.
It should work again.
The same thing happened to me, took me an hour to figure out.