Fun fact: Windows XP had cool day 0 loophole that saved my my ass. Once I decided to explore new options and I stumbled upon new and cool feature: setting a password. The only issue with it was that I've forgotten it half an hour later. I already knew 'admin' word so I used it in hackerman style and I logged in and I was able to reverse old password. This loophole was patched with first service pack but I still giggle when I remind myself of that.