Try looking into custom menus. It works for us.
In Manage | Security, you can create your own privilege set to be used with this account. You can select options that do not allow deleting records. For example, one option is "Create, edit and delete in all tables" another is "Create, and edit in all tables". Note that "delete" is not an option in the second choice. You can also set more finely tuned permissions table by table where delete can be specifically controlled for a given account or even for records with a specific value in a field.
In our DB, we use these settings to keep employees from deleting or modifying an invoice after it has been printed.