Okay well for a short period of time I could play GTA:SA/SAMP on my new PC which has Vista x64 on it. I remember trying to install a mod one day which caused it to crash when loading, so I did a complete reinstall and the problem still remained. This occured on my dad's pc which is just XP but I eventually just reinstalled one day and it worked, so I have no idea why reinstalling isn't fixing it. I may try dling another GTASA torrent to see if that's the problem but I don't think it is as this did work earlier.