How to get the Administrator Password on windows machine?

Question

I have a good friend, whose Microsoft screen saver started acting up, and they couldn't shut it off, so, using the shutdown function, turned the computer off. When they turned it back on, their password no longer works.

Any idea what happened? Or better yet, how do they get back into their computer? (No, they do not have a password recovery disk.)

Answer 1

I might take that bad hard drive, set it up as a secondary on another machine and point MSE (microsoft security essentials) to it to find out if has been attacked by a virus or trojan. If so, letting MSE clean it up might solve the problem.