Have you looked at the documentation link provided by Mary C? Or the links above that? And it is still not deleting? If so, then are you an Admin of that Moodle? If not, then you will need to talk to an Admin. If you are then the only other way I know of deleting a course is by accessing it directly in the database. If you do not have access to the database, then discuss it with your System Admin, they should be able to assist.
General help
delete a course
This discussion has been locked so you can no longer reply to it.