If you mean that they installed Moodle on a server from the Windows "one click" installer found on this site then you need to consider that the package is only intended for testing and evaluation. Xampp on which it is based is not configured for 'production' (server) use.
If that's the case you should consider backing up the data (database plus 'moodledata' directory) and then install PHP plus webserver (IIS probably) and MySQL 'properly'.
Unfortunately, I have zero Windows experience and cannot be much more specific.