Most times, it's very difficult to get backwards compatibility. The older software may not have been written to the operating system's standards, and so won't have the proper "hooks" into the new OS...many programs, usually games, did direct writes into the system rather than use the kernel's built-in libraries and routines. It made the game faster, but eliminated a lot of compatibility. Some programs are old enough that they expect to see the 16-bit file system and can't address the modern system. The list can go on and on and on. You really need to check with the software maker to see what's going on. The maker of the OS cannot address all the different things the thousands of programmers have done to their own little corner of the software world.

Finally, at some point, you just have to write-off old software because it is just that: too old. Don't expect your old 8-bit software to work on the modern 64-bit machines...even if it is your beloved game of caterpillar or Pong (R).