I can currently login to ubuntuforums with my old account and password or by using my launchpad account. It is my understanding that they both link to the same account. I would like to prevent login using my old ubuntuforums username and password so that I can only login to ubuntuforums with my launchpad account.

Is there a way to do this?

It would put my mind at ease and simplify the startling number of online accounts I need to keep track of.