Please make sure to uninstall all the previous FG-X and Slate Digital files.

Your issue is more likely linked to a corrupted option file.

1)  In the Windows Device Manager, click on Dongles, right click the iLok Device and uninstall it.
2)  Physically unplug the iLok USB Device from the USB port
3)  Re-download and reinstall the Slate Digital FG-X
3)  Reboot system
4)  Reinstall the iLok Drivers
5)  Physically plug in the iLok USB Device into the USB port
5)  Rescan the VST folder in the host DAW

For some DAW's, FG-X needs to be placed in it's own labeled folder inside the VST, AU, or RTAS plugins folders where all your other plugins are.  If everything installed correctly, there are no iLok issues, and the plugin won't appear in your list, try creating a folder called "FG-X" in your plugins folder and moving the .dll file in there. Then, reboot your system and start a session.