One can set the the 'Create' pop-up menu in the users' privilege to 'no' for the table in question.
Edit the account privilege set (or create a new one) for the users and set the Records pop-up menu to 'custom privileges'. Then you can choose the table and set the Create pop-up menu to 'no'. (You may also want to set the Delete pop-up menu to no as well.)
Add a single default record using the admin account.
You can make all the fields in the table globals. But this may cause problems in a multi-user solution.