posting after skimming the topic, so bear with if i miss something
you could try getting an Enterprise (theres a few in the internets, try YAP-RW models page) and running in a clean install in 1975
if that works, run single mission in your SF2V Expansion install
if that works, edit the campaign to use the Enterprise you picked
if your gonna do any modding for SF2, best to keep a clean install (exe) to check things in. clean it out everytime you are satisfied with what youre checking
out of curiousty, how is your install? some games (like just SF2Europe and Vietnam), full 5 plus two (all five base games plus the two Thirdwire expansion packs) or the all in one (Thirdwire release from a couple of years ago that has everything TW released over the years for around 100 bucks)?