You will find the FGx 2.4.0b4 beta for windows installer here:
http://code.google.com/p/fgx/downloads/ ... up-2.4.exe
"Windows Installer for WIN32. Downloading and running this installer will give you a desktop icon to use to run Fgx. The default install will be to 'C:\Program Files\FGx', and requiers about 40MB of space. And it includes an 'uninstaller' - in 'Add and Remove Programs' Control page."
You need a pre-installed FlightGear to run with FGx. You can also try to use hudson builds or "self-compiled" versions of FlightGear of course. Enjoy, test and report FGx related issues to the FGx bugtracker . Thanks !