RE: GP Real Flight 95
It should run on XP. My kids have RC Pilot on their XP machine. It was Knife Edge's sim just before Realflight.
If you run into problems with it, right click on the desktop icon, click on properties. Click on the capatability tab on top and tell it to run in compatability mode for windows 95. I didn't have to do all that for the program I have though.