Linux Live

So far as this writer knows, the only install-it-and-go Windows domain controller in Linux, is Calculate Linux:

http://www.calculate-linux.org/en

which appears to be a very well-established distro, Gentoo-based.  There are semiseparate client and server distros in this flavor.

If your boot loader is ‘grub’ (highly recommended), a very good method to reset your root password is described here:

http://www.debianadmin.com/how-to-change-root-password-in-debian.html