As Striek said if you can get physical access then you'd take why you need then.. why risk going back a second time to dump your backdoored SAM file... if someone really wanted access again, they'd obtain it the same way they did the first time



You can't just have complete access to the box with just physical access, can you ?.
All you need to get the SAM file (as i've earlier said) is just a live cd or something like that. Without any kind of privileges you could get the SAM file. Get the SAM file, Crack it. Some back
later (maybe after a few months ) and assuming the administrator didn't change his OS, you
could be root and do all sort of stuffs!. You've seen the movie THE FUGITIVE, haven't you ?.