My daughters computer is having problems with xp user accounts.

Originally it was setup with an admin account called Lachlan. She renamed this to Lauren. In the user accounts section of the CP it shows 3 user accounts, Lauren, Guest account which is off and an ASP.NET account.

However in the docs and settings folder thisa ccount is still called lachlan and I am unable to change it to lauren.
I tried to follow a KB article that said to run winnt.exe orwinnt32.exe except neither of these progs existed on the pc (Win XP Pro)

I also followed another KB article that said to chnage the sid in the registry of the account to the one it should be but then it just showed a folder in docs and settings called lachlan.lauren

Any ideas how to fix this?