Check md5sum to make sure ISO is genuine. Oon windows, simply drop ISO on md5sum.exe from here: http://www.etree.org/md5com.html
Use unetbootin (or imagewriter) for “burning” the ISO on an USB stick or write it directly to DVD.
Please turn Secure Boot OFF and select non UEFI boot option from invoking boot menu (F12 during boot) of your BIOS, see our Readme: http://www.netrunner-os.com/readme-1312/
If you run Netrunner in a VirtualBox, please use the 32bit version, 1 GB RAM and 10 GB diskspace.