Members can not delete a topic. MODS however, can lock your topic is you wish. Simply change the title of the topic you wish to lock to: {Please Lock}. Once you do that be patient and wait for the staff to see it so they can lock it for you. Locking a topic lets others see it, but not be able to post. I am not POSITIVE if MODS can delete topics, but that is only because I've never seen it happen. Anyway, hope that helped a little.