Hello again!
Your flysky radio outputs a stream of signals (as most do) from the socket on the back. This stream can be plugged into your computer audio input. But you'll need a couple of programs for the computer to make sense of it.
1.
Smart Propo Plus
2.
PPjoy
These will work on windows 7, but if you have the 64 bit version, you must disable driver signing enforcement on start up of your computer. This is easy to do, just hold down f8 while your computer boots, and it will give you several options like safe mode etc. near the bottom of the list is Disable Driver signature enforcement. highlight that and your good to go. You will, however, need to do this each time you wish to use these programs.
Once you have these working, then it should allow you to use just about any flight sim you wish. I use
Clear View, though its not free, its about US$40. It does have a free demo version with a few planes.
But you'll get many different answers on which flight sim to use, there are many to choose from. As for free, i guess
FMS, but I've never got it to work properly. I havent looked for a free one in some time, so there may be better options available.
Good luck!
NAM