I just wasted 2 hours of my life trying to figure out why FS2004 wont run on windows 10. It was all working fine on previous laptop windows 7/8.1 Feeling a bit guilty about not using it as much as I should, I resolved to do something about it this evening. I am however migrating to a new hi spec PC and have upgraded to windows 10.
All the files have been re-installed correctly, however I am made to understand that once you down load the Flight Simulator 2004 Update v9.1 update its no longer required to have disc 4 in the drive for it to operate, and it is supposed to cure a host of other problems in migrating to windows 10
It is still however asking if I want to allow the program to make changes and then when okayed, does absolutely nothing. The software does not fire up. I've seen that a lot of people have similar issues with windows 10, and I have tried most of the solutions discussed but have had no luck yet.
Just upgrading FS9 to 9.1 improves the Sim.
You need the proper crack (no-CD-patch) to get rid of disk 4.
Here it is, let us know how you do.