Windows 10users face this problem usually. There are loads of fixes on YouTube for that. Thought thats the issue.
However, at this point I am not sure what the issue with the game is if you are not even using Windows 10 but If your problem is occurring since you installed GTA SA, then it is a problem with your game most probably. Try downloading it from some better website maybe. I dont have any other possible fixes in mind since i never encountered such problem(nor did i ever use win7 32-bit)