I will recheck your permissions.  To locate particular users, I use the "Buscar usuarios" link.  Each picture in the table leads to the user's page allowing you to make administration changes to the account.  I don't know if you have seen the link, but there is a "manage content" link that utilizes something called bulk operations.  It's super powerful (and very very dangerous), but it allows you to mass select content and modify it.  For example, I used it to remove all the calendar items that defaulted to the front page.  There were over 400, and I just selected them all in the manage content page and with one click removed them all from the front page.  User operations can also be exposed to bulk operations.  It's really easy to delete everything from the site, though, so I don't know how much power you want to wield.  With great power comes great responsibility :-).

As for the active normal users.  I didn't actually mean to block anybody, but there was a setting when I was importing the users and I screwed it up and started notifying the former admins about their accounts.  When we went live, I was going to reset all the accounts to "inactive" and then reactivate them causing the notification email to be sent out with the link for password change and information update.  It doesn't really matter at this point, because nobody knows their account is "active" anyway.  They didn't get any notifications or anything, so the site is still effectively hidden except for a few of the admin users from the old site.