Sylvia,
Is this webhosting company a Moodle organization or is it a regulary webhosting company?
Did the hosting company give you an adminstrative user name and password? Or if you uploaded and installed your own Moodle software, do you remember the admin user name and software you used when setting it up? That may be what you need to get in. If it is a Moodle hosting site, you may need to contact the hosting company and have them help you with the admin user name and password.
Another thing to check is to make sure you are trying to register on the correct site. When we are first getting started it can be confusing. .( 
Been there)
Paula