ok, let's try to get you working.
first unplug your GX then in add remove programs, run the line6 uninstaller and remove everything.
now, 64bit drivers are available. what I would do is install pod farm v1.12 but don't connect your GX. then go here: http://line6.com/software/ select your OS, your GX and also drivers in the list and download the latest version, then install them, and then connect your GX, see what happens.
try every different USB port on your system, and disable all other unused hardwares and applications. unplug all other USB devices that you don't need, so that's printers, scanners, web cams, HDDs, memory sticks, hubs, etc. just leave your mouse and keyboard if they are USB.
if it's still not working, then come back.