Sorry to post the same thing again. I read all the stuff that was in the site about this topic but they were giving me two informations.
When I searched under rules, for delete thread or post, I got this info,
If you have registered, you will be able to edit and delete your posts. Note that the administrator can disable this ability as he desires. Your ability to edit your posts may also be time-limited, depending on how the administrator has set up the forum.
To edit or delete your posts, click the button by the post you want to edit. If your post was the first in the thread, then deleting the post may result in the removal of the entire thread.
So according to it, I must be able to delete my thread. But reading some other threads from the authorised authority, the information was that I can edit my thread within 15 minutes.
I really need to delete at least my post in one of the thread or at least one reply which got codes cause I found out that I was not supposed to publish my codes. So can someone please tell something or direct me somewhere.