Change registered user name

Thanks for the help,
Tim
>-----Original Message-----
>Hi,
>I just sold my computer to a freind and want to know how
>to change the registered user name that appears in the
>system properties.(Right click on the my computer Icon
>and click properties).
>In the screen that shows the operating system and the
>amount of ram processor type Etc.
>Nay help will be appreciated,
>Thanks,
>Tim
>.
>