Thread:Project:Support desk/old mysql database resulting in Cannot contact the database server/reply (14)

Puhh, hard to fix, when there suddenly are new problems arising.

I expect that the MySQL server now is fine and that your data is in a DB in it. Maybe you have another application or maybe even the command line to test, if you can successfully connect to the MySQL server and use the DB - using those credentials, which you have in LocalSettings.php. That should work now; e.g. you should be able to count the rows in the text table.

For the error 500 have a look at the Apache error log; it is most likely located somewhere inside the apache/ folder. It should have more information on the reason for the error 500.