You can only delete a non-posted job. If you want to delete a posted job, you must first take it down (make it inactive), then delete it.

To permanently remove a non-posted job, select Permanently Delete Job from the Change Status pull-down menu on the Jobs tab showing all your jobs, or from the Job Actions pull-down menu on the Job Detail page. The job and its links to candidates will be removed from the HotJobs database and will no longer be accessible to you.