they are both listed in my pull down menu
It's not clear from your message, if both menus are still there after you see the scenery disappearing. If the Couatl menu is there, try to use the "Restart Couatl" option from its menu.
If it's not there, then it means it has stopped with an error, so you should enable Logging from the "GSX Settings" menu, and after it stops, exit from FSX and check if you have a Couatl.err file in your %APPDATA%\Virtuali folder, then post its content.