There is no definitive answer , no definitve solution seems like over the time people got it working with their own fixes , this is a bug in the hardcode and we can't find it unil the devs do something , with IW being pretty much done for , there's no way activision will go and patch the old games.
I can't point this out enough , that a 2005 mediocre PC can play the game fine while a 2008 high-end hardware can't , this is just a lot of stuff , you never know , maybe microsoft and their stupid visual is to blame (every PC has to have it's very bad methodology of weird libraries installed, that's how SFC may fixed the problem)
