Check under Device Management in Windows and make sure the GekkoScience 2PAK is showing up all the way at the bottom as a Universal USB Device (something named along those lines.)

You need to make sure that the GekkoScience 2PAK is not accidentally being read as a COM Port Device by Windows.  If you see a COM Port Device that appears to be your GekkoScience 2PAK, simply click the listed Device and uninstall it, then use Zadig again.  Unplug and replug in the USB miner and keep checking that it is actually labeled as a Universal USB Device, which Zadig effectively makes the system read it as rather than a COM Port.