Unfortunately, sometimes we cannot log in into Windows-system because we have lost or forgot password local administrator account.
Fortunately, there is a way to reset this password ;). Now I will show you, how to do this. I recommend to add this article to your bookmarks, to have this manual when you're really need it :-).
First of all, you will need to download this iso image. We will use it to reset password. Burn image to CD-disk or mount it into your virtual machine (in my case it was exactly in VM). Boot from the image.
After booting, you will get the following picture.