Download a live Linux distro and boot up from that instead if possible. Since everything runs off of the disc, it will not touch your system files and you might be a whole lot happier using that instead.
Unfortunately, this particular machine is the controller for a small CNC mill (Roland MDX-40), whose dedicated software requires Windows to run. I had it running from a Dell laptop, whose screen died. If I knew then what I know now about W8, I would have paid to have the screen replaced.