Here's something you can try.

1. In windows explorer (the file manager) browse to the installed realflight directory.
2. Right click on the realflight exe file (don't know what it's named but it should be only .exe in the directory).
3. Then in the right click menu click the properties option at the bottom. A tabbed dialog will display.
4. In the tabbed dialog click on the "Compatibility" tab.
5. Check the box that says "Run this program in compatibility mode for:"
6. Select windows 95.
7. Click OK

Now try to run the program again. It might work. I was able to run an original install of Duke Nukem 3D on XP doing that. It was odd playing that game again. I remember it being so much better lol.

Good luck