stefanaalten wrote:"Database connection error (2): Could not connect to MySQL.Database connection error (2): Could not connect to MySQL."
That means, you (once) configured your Joomla Installation to work with a certain database. If you forgot everything, it is getting difficult, because here nobody can know what you specified years ago.
Additionally, if you removed the old Xampp Installation and installed a new one, you probably might have deleted the old database, which results in a total loss of all Joomla data. You should restore the old Xampp installation, otherwise your Joomla installation wont work anymore.