Installing and upgrading help

About the only way that might happen is when Moodle can't find/read a config.php file.

So ... check the moodle code directory for a config.php file.

Is it readable by all?

If no config.php file, contact hosting provider ... hopefully, they have a backup of your site and could restore the config.php file. ** see below

Failing that, one last chance ... but it involves a little mysql and editing in re-creating a config.php file from the config-dist.php file that should still be in the code directory.

First, gather some information concerning the DB ... remotely hosted systems usually have some tool installed for customers to do that.   You need: DB host, DB name, DB user, DB Password.

Use a mysql query tool to view the contents of the mdl_config table.

That should contain all the variables that were in the original config.php file that you could manually insert into a copy of config-dist.php which you *copy* to config.php.    You'll see lines like:

$CFG->dbhost    = in a copy of that config-dist.php file now called config.php.

The value would be enclosed inside the 'ticks' and each config line would end with a 'semicolon' (;).

The following for typical mysql on linux:

$CFG->dbtype    = 'mysqli';      // 'pgsql', 'mariadb', 'mysqli', 'mssql', 'sqlsrv' or 'oci'
$CFG->dblibrary = 'native';

Web site location

$CFG->wwwroot   = 'http://example.com/moodle'; (url to your moodle site)

Full path to the moodledata directory:

$CFG->dataroot  = '/home/example/moodledata';

The above is an example ... can't copy and paste it.

The rest of the config.php building you could skip.

Make sure it's readable by the globe.

Then try hitting site with browser.

** see above ... would be by ar the easiest way to fix! ;)

'spirit of sharing', Ken