No hack is required for me to do this on almost all machines.
I either boot safe mode or like most folk they leave the machine logged in or set an autologin and I'm able to make my new account admin in under 60 seconds.
Let's say you can't log in as administrator? Why not use NTPASSWD to reset the password and get in?
Bob
Now add some detail so that smart CNET users (like you!) can answer. If you're lucky, a CNET editor might choose your topic for a How To article or video.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic