You don't need FSX to become a virtual controller. In fact, you don't need a flight simulation program at all. The built-in ATC function of FSX (Deluxe version only) is only one of several ways to be a controller.
The FSX multiplayer system that allows you to be an air traffic controller is really just a control tower simulator; you're looking out the windows of a tower, visually sequencing other multiplayer pilots to and from the runways. The FSX tower controller position has a basic radar screen, but mostly you're looking out the tower cab windows.
The simulator's basic radar screen is OK for use as a radar controller (such as approach control), although in that function it isn't nearly as good as a stand-alone program on an online network. But it certainly is easier to get started, because you already have all the software you need.
ASRC ( Advanced Simulated Radar Client) is a Windows-based program that is use by VATSIM ATC Controller. It is intended to replicate the radar screen that real controllers use for approach/departure control or, by changing a setting, the radar screen used by en route (FIR/ARTCC) controllers.
ASRC is free to download and free to use on VATSIM ATC . Extensive documentation is also available to teach student controllers how to set up and use ASRC. Once you have the software, you can begin training to become a controller.
Note: This mission is a copy of the Chap_BC2_Line_Check mission and has been created to provide access to the additional documentation of the book, within the FSX Mission environment.
Ref.: West, Jeff Van. Microsoft Flight Simulator X For Pilots: Real World Training. Wiley. Kindle Edition(Location 13868).