Are you trying to search for your own posts? Just click on your username and you will come up with a profile page that shows all of your posts. The same is true for other users who have posted to the forum--click on the user name and you can see all that user's posts.
Yes I'm looking for my old posts, but that was under a different user name and an old defunct email address. So rather than try to revive it I just created a new account.