Spyfalcon installs itself on computers because the owner inadvertently clicks 'yes' to a scan or something innocuous. No firewall, programme will stop it as you have given it permission.
Download ewido from click here and run it in safe mode.(turn on computer and keep tapping F8 until you hit a B&W screen. Choose safe mode by using the up/down arrows on your keyboard an hit enter). Delete all it finds.