What do you mean by "I'm actually having trouble exactly where you're seeing the abcd one." ?
I'm using "ABCD" as an example user name (do not want to put my real user name here)...I'll try to elaborate on the above:
Keep in mind ABCD is a not my real ...anything, just an example.
1) Going to Control panel, system computer the name is "ABCD-PC" and full name is "ABCD-PC"
2) Going to Control panel, user accounts...the name implies THIS is the user, there is only one user account, it is the local account, administrator and is "ABCD"
3) in windows explorer, going to the directory C:\Users\ there are the normal directories, and "ABCDZ": ....when logging in via a remote app..say real vnc...I have to use "ABCDZ" as the user id. (below are all directories under C:\users\)
All users
Default
Default user
default migrated
Public
ABCDZ
4) when the lock screen comes up with ABCD...and of course the empty password field..again the acct name.
So? I ask:
1) What is ABCD ? is it the account name or user name? if its account name, why is it in "Control panel, user accounts"
2) What is ABCDZ ? its obviously the user id as far as Real VNC is concerned.
3) Where would you edit the user id (ABCDZ) it is not in control panel, user accounts?