minor user name problem

Hi, all -

I've just set up a Vista install and I made a minor error entering a user
name - I hit the apostrophe when I went to hit enter, appending an apostrophe
to the end of the name. I can't seem to correct it. I've tried changing the
name via the user account panel, I've even gone so far as to completely
delete the user account. Still, whenever I install an application in that
account (one that reads user information), the name with the apostrophe
appears as the initial value for user name. (I mean in Office or Visual
Studio, when it asks for user info during setup.)

Does anyone have any idea where the registry key with the string for user
name lives? I'm quite comfortable tweaking the registry, if someone could
point me in the right direction.

TIA...