How does a person reset the admin access?
Moodle 1.8 and php 4.3.0
You left out the most important detail: database type!
I'm not 100% sure, but looking over the contents of some of the tables in my Moodle 1.8.2, it looks like the answer is in the table (assuming they're using the default prefix mdl_) mdl_role_assignments using numbers defined in mdl_user and mdl_role. For example, in my database, in table mdl_user the id field for the admin user has the value 2; in the mdl_role table the id field for Administrator has the value 1. So user 2 needs to be assigned role 1. Sure enough, in the mdl_role_assignments table, in the only row the roleid field has the value 1, and the userid field has the value 2.
So you need to look in those three tables and see what change needs to be made to the mdl_role_assignments table. For example, if in my table the roleid field was 6 instead of 1, that would make my admin user have the role of guest, like in theirs. So I would have to change it to 1 using a SQL query like this:
update mdl_role_assignments set roleid=1 where userid=2;
If the school is using a GUI tool like phpMyAdmin (which I don't have installed and know little about), then you could use that instead of a SQL query, or you could use it to execute the query. That's up to you and them. But you know what needs to be done: backup the database first!