Offline NT Password & Registry Editor (ONTPRE) is an excellent, and arguably better, alternative to the very, very popular Ophcrack password cracking program.
My review of Offline NT Password & Registry Editor has been a popular stopping point on my site but the biggest complaint about this unique "password removal" tool is that it's a bit hard to use since it's all text based.
So in response to all the feedback, I've created a step-by-step guide with screenshots, demonstrating every painless step in great detail:
I should also mention another program called PC Login Now which is a password hacking tool that works in nearly exactly the same way as ONTPRE but it does so with an easy to use graphical interface.
However - PC Login Now causes Windows to believe there has been a hard drive issue, which is a little strange. In my opinion, you shouldn't need to use PC Login Now - ONTPRE is just as effective and now that you have a step by step guide to using it, it should be easy.