There's supposed to be a factory reset button on it somewhere, probably recessed, that you'll need a paperclip to get to. Can't speak from experience, but that should do it.
Obviously, don't go probing in every hole looking for the button with the power on!
The Samsung BD-1600 I bount was an open box item and has a Netflix account already activated on it, but is not mine. How do I deactivate the account that was previously set up to get an activation code to enter on my account? I would so appreciate removing the instant Queue with all the horror movies and be able to see my selections.