Howard Miller

I'm not sure this is possible... although you can reduce the information displayed to a minimum (Site administration > Users > User policies).

Moodle isn't really meant to work that way. For example, how would a Forum work if users couldn't 'see' each other?

As previously explained - your 'emergency' setting in config.php will lock out everybody else. So, assuming nothing else changed, removing that should restore all the other admins and one of them can reinstate you.

The "right" way to deal with this sort of thing is via the "primary" site administrator. This is the administrator you set up when the site is created, has id=2, and (if you didn't change it) username 'admin'. Personally, I would always recommend keeping that user as a separate admin not connected to any real user. Keep it under lock and key for emergencies (such as this). If you loose the password, there is a command line tool to recover it.

Ask the person who deleted you to put you back?

The problem is that the config setting is a comma separated list. So you are overriding the setting through the admin interface and effectively saying "admin is just 4359".

At a pinch, you could simply add the additional IDs in config.php, e.g....

$CFG->siteadmins='4359,1234,7890';

Change/add the numbers to the user ids required. However, I'm going to suggest that what you did to solve whatever problem you had in the first place may not have been the best solution.

Start by opening the Javascript console in your browser (F12 + click the 'console' tab). Recreate the problem. Any red error messages?