Please see the screen shot below. In the pink circle you see "Edit". You can edit your messages with this. Also, if you click Edit on the original message in the topic that you started, you can edit the title of the topic. Also you see "X". With this, you can delete your message. But deleting the original message in a topic does not delete the entire topic, only that message. If you want an entire topic deleted, you should PM (Personal Message, in User Control Panel) a moderator to discuss it.
