Account Unknown - Botched SID Change

Earlier I tried using NewSID, which "hung" up on Vista Premium. Then I reset
the SID using the Sysprep that comes with Windows, just to be safe. However,
I didn't know that this was going to reset the system to where I have to
create a new user, and leave the other to sit and take up space. I want to
get the old username back, however it's not listed in the accounts, but you
can see the data still saved by viewing the profiles. You can also see it
during setting permissions to folders, etc., but again cannot edit it.

The current SID is: S-1-5-21-2757170329-234990091-661126355-1009
The previous SID was: S-1-5-21-3672849985-1281681111-27197576-1000

My previous account should have changed SID to the new one, but didn't and
still shows up as the old one.