Don't use the disc.
Download from here:http://fishsim.net/fs2down.htm
However, you must then install the update from here before you run it in Windows 10, making sure you install the updates to the same folder that the original installation is located in.http://fishsim.net/update.php
FS2 should then function properly but there is one more update around 2.13g that fixes a problem with hair rigged baits.
Once you are happy that all is working, I can provide a link to 2.13g.