Random CTD HELP!!
To add one thing, start a new game to eliminate possibility of corrupt save game file. A reinstall will not replace all your files unless you do a clean reinstall and manually delete everything. Remember that changing your installation folder, if you choose to do so, will not change the other Rockstar folders used by the game with fixed locations such as my documents.
P.S. i didn't read the entire thread but it seems you never confirmed if your game runs in pure vanilla? Thats the first step. If it does run you can effectively rule out all hardware and windows related causes and focus on your mod folder structure and mods.