Can't change default user name on Authentication dialogs

Question

Due to a corrupt user account, I had to create a new user account. I specified a "2" at the end of my full name i.e. "Full Name 2" because I couldn't use the same full name as the corrupt account.
I still haven't deleted the old corrupt one yet just in case I need something, however, now that I am using the new account I renamed the new account to "Full Name" without the "2" at the end of it, but for some strange reason OS X still uses "Full Name 2" on the authentication dialog boxes.
Just to summarise, I do not have an account called "Full Name 2" anymore - I've even updated the contact record - and when I get asked to authenticate via a dialog box, the name defaults to "Full Name 2".
Not sure why it's still doing this and how do I get rid of it - I just it to default to "Full Name".
At the moment I can login with both "Full Name" and "Full Name 2".
I tried deleting some preferences and re-log back in - but this didn't do the trick, but admittedly I may not have trashed the right ones.
Please help.
Thanks.

Answer 1

First, I create a new user account via System Preferences -> Accounts. I gave it a different account name and I entered the same full name. It rejected it saying the full name was already in use, so I renamed the full name to "Full Name 2" just to I can create the account.
Then, I logged in to the new account. Tested it, set it up how I wanted it.
Then I logged back in to the old faulty account, and renamed the full name from "Full Name" to "Full Name OLD". I did this via Accounts. I simply double clicked the old account and the edit window showed up. I just renamed the full name field.
I then edited the new account, and renamed the full name field from "Full Name 2" to "Full Name". Since the original account now had a different name, I was now able to rename the new account to the desired name, i.e. without a "2" in it.
However - now it shows a 2 in the default account name whenever I need to authenticate something.