Hey There,
If you are trying to load a save game that you have downloaded it might be the wrong version so go to http://hmvartak.110mb.com/conv.htm and convert it
also when you place the savegame file make sure you save it to C:\Users\YOUR NAME\Documents\GTA San Andreas User Files
if any of that dosent work try: 1: upgrade your computer
2: buy a new computer with better specs
HOPE THAT HELPED!!!
Cairo