I got a Windows 8.1 PC and wanted to reset the password for local administrator account. A reset was not successful so I switched to using a Linux live image.
To do this I downloaded an Ubuntu 16.04 Desktop image and wrote it to a flash drive using RosaImageWriter (see link list below) and booted the machine with it.
I downloaded the deb package and installed it using
sudo dpkg -i Downloads/chntpw_1.0-1_amd64.deb.
After mounting the Windows partition I navigated to
<mount point>/Windows/System32/config and started
sudo chntpw -i SAM.
ROSA Image Writer
Available for Linux and Windows.