MacBook Pro: change registration/user?

1. Boot to single user mode by restarting and after the chime press and hold down the COMMAND-S keys until a black screen with white type appears.

2. At the prompt, type the following commands pressing return after each command line:

/sbin/fsck -yf

If you do not receive a "Filesystem OK" message then repeat this command until you do. If after seven tries you still do not receive a "Filesystem OK" message, then the system is corrupted and needs to be reinstalled.

mount -uw /
cd /private/var/db/netinfo
mv local.nidb local.old
rm ../.AppleSetupDone
shutdown -r now

The second-to-last command above will cause OS X to think that the operating system is newly installed, and when the new owner starts up the computer it will send him/her to the startup wizard where he/she can start a new user without reinstalling.

I note you have SL. The following applies to Leopard as I do not know if SL works the same way.

Go to System Preferences/Accounts
Are you listed under "My Accounts" as the admin? If so, you will be able to unlock the padlock if it is not closed so that you can make changes.
Click on "Log In Options" at the bottom of the "My Accounts" window. Look for "Automatic Login" near the top of the window. You will be able to disable this option.

Go back to the "My Account" window & click the "Change Password" button. You should be able to add your own password.

Lock the padlock

OOPS! Nature called right in the middle of posting a response. Kappy already responded. Disregard my message if Kappy's suggestion works out for you.

No, it won't delete anything except the indicated file. The location has changed in SL. Change the instructions to:

cd /private/var/db
rm ../.AppleSetupDone

I believe this should accomplish the same result. After the reboot the Setup Assistant should run. You can then change the initial admin account to your liking. After you leave the Setup Assistant you can use Accounts preferences to remove the other user account. Note that when you do that all the files within that user folder will be deleted.

Try rm .AppleSetupDone

Don't forget there is a period (.) before the AppleSetupDone.

I don't understand. Here's what to try:

(1) Restart --> Press & Hold COMMAND-S, then
(2) cd /private/var/db
(3) rm -rf .AppleSetupDone
(4) reboot

Ooops I apologize. It should have been "rm -rf" not "rm -rt". A typo on my part. I'm not making this any easier for you, am I?

I'm pretty sure we went through this earlier but you must start with:

/sbin/mount -uw /

before you can actually delete a file. Enter this as soon as you have booted into single-user mode.

Sorry it got so drawn out.