Trouble with name/registering account

Hello, I've been on these forums before. I tried to sign in to post up on the forums and it's telling me my real last name and first name and middle initial. I don't want this showing up when I post up on the forums. Secondly, I tried to re-register thinking that would help so I could change my name, it won't let me do that either. I enter the code, it says kindly enter the code. I'm entering it exactly as it says on the page, it's still giving the message to kindly enter the code. All I want to do is make it so that it won't show my first and last name when I post on the forums, i'm a very private person and want to keep it that way. Any help is greatly, appreciated.