Questions which fulfil certain criteria such as having low score, no answers, few comments, few views, being closed etc. are automatically removed after a certain time. For details see
As to deleting a question of yours yourself, you can do so, but I suggest to do it not too
often. Also I suggest you to take into consideration that people may already be working on
writing a good answer for you, and may not like it to see your question disappearing
immediately before they are done. To minimize these concerns, you may either delete your
question very quickly (say after a few minutes, i.e. before anybody may have put significant time into thinking about an answer), or wait at least a couple of days -- but these considerations depend quite a bit on the particular case.