Basically i want to delete the one and only user on my osx install which is the Administrator. So the machine goes back to where ou first setup your system when you turn it on for the first time.
However when they fully run threw, it has latest updates and all previous software installed.
In tigar this was possible by doing the following
How do i do this in Leopard?
Boot into single-user mode by holding cmd-S at the smiley Mac at boot.
Type 'nicl .'
'list /users' should give you a list of all known users.
'read /users/<username>' should give you all the data for that user.
'delete /users/<username>' *SHOULD* delete that user's entry.
'quit' exits you from nicl.
'cd /private/var/db/' at the command prompt.
'rm .AppleSetupDone' This is the file that, if it's missing, the startup sequence fires off that funky "Welcome to MacOS X Setup" sequence I think you're looking for for the next person to play with.