Delete discussion board thread
Students can edit and delete their own discussion board post or thread only if the instructor has enabled those settings.
1. Click on your course in the My Courses module.
2. In the course menu, click on Discussion Board.
6. Hover your mouse over the original post, and click the Delete button once it appears.
7. When the warning message comes up, click OK.
NOTE: Deleting the original post in the thread deletes the thread and all the replies to the post.