For other users reading this who need to find a fix.
The problem was the local user and groups, or the user management in the control panel or even the ADSI code programs use to pull the user accounts would all return nothing.
This is because this is another part of Windows where if there is an error of any kind it simply bombs out and doesn't list anything. Yet if you open a cmd.exe window and type in net user, it will list all the users just fine.
In this case the problem was in the registry.
If you go to
HKEY_LOCAL_MACHINE\SAM\SAM\Domains\Account\
You will see two sub registry keys, Users and Names.
So as an example you may see something like
HKEY_LOCAL_MACHINE\SAM\SAM\Domains\Account\Users\000001F4
then under Names the name that belongs to that key will point to it, in this case
HKEY_LOCAL_MACHINE\SAM\SAM\Domains\Account\Users\Names\Administrator
Which when you look at its value points to 1f4
So in this section there was more registry keys under Users then there was under Names (This should normally have the same number of items) There was also 2 Names registry keys that pointed to the same path.
Once I got rid of all the extra folders that didnt point to anything and got rid of the duplicates the user accounts started showing up fine again.
So the problem was all because of some extra registry keys being in those paths.
Shane