Hit the start button, type %appdata% and hit enter, then hit AppData, Local, Rockstar Games, savegames, then there should be a folder with your savegame info, mine is user_e0000029b62789d5, open it up and delete ALL SAVEGAMES, but not the Controlmap.dat as these are the keybindings, and if you delete these, you will have to customize the keys all over again. Hope this helps!