The Coutl Menu is not visible on Modules.
The Couatl Powered plugins menu is not supposed to be under the Modules menu, but under the Addons menu, together with the Addon Manager menu. You should see both menu items.
Have you got a request to trust the Couatl module the first time you started FSX after installing LSGG ? If yes, have you replied "Yes" to both questions, the question posed by Windows, and the question by FSX ?
Can you check your EXE.XML file, located at %APPDATA%\Microsoft\FSX if the line launching Couatl has been added ? If it hasn't, please post the content of that file here, perhaps it was corrupted already, so the installer hasn't touched it.
If you see the line in the EXE.XML, perhaps you have not trusted the module so, you can reset the trust request (so the question can be made again), by editing your FSX.CFG located at %APPDATA%\Microsoft\FSX, going under the [Trusted] section, find if there are any lines containing Couatl.exe and remove ALL lines (the WHOLE line) that contains a reference to Couatl.exe. Save the file, launch FSX and notice if it asks you about trusting the module. Reply "Yes" to both questions.