How Do I delete a Post?

Thirteen days ago, in the Laptop forum, I posted a message entitled Precision M4700 Questions about a computer that I had ordered but not received yet.  My questions were not about delivery (in fact, my M4700 arrived eight days before I expected it).  Instead I had some questions about some M400 features.  The message is at http://en.community.dell.com/support-forums/laptop/f/3518/p/19488511/20285989.aspx#20285989.

But after 13 days no one had admitted reading it, much less responded to it, and it is now out of date because I have now received my Precision M4700 and the questions I posted here have been answered by Dell technical support.features.

1) So how could I delete my outdated post?  Or are dead posts that no one was interested in deleted automatically after a certain amount of time?

2) A minor item is that I mis-numbered two questions, but I didn't realize notice until several days after I had completed my post.  There was no way to edit it, so I "answered" it by posting the corect numbers.  But is there some way to edit one of your own posts on a website?  (Incidentally, at MozillaZine, and at the Wilders Security Forums, it is possible to edit your own post after you have completed it posted it.)

These questions aren't important, but nevertheless I would appreciate an answer.

Roger Folsom