When I purchased the game I received 4 different installers and a patch. All of the installers are markerd as part 1,2,3,4 so i started installing the first one. I got a messege that ''Part 3'' isn't in the selected folder and that files were missing. I created a new folder and downloaded all of the installers and then I put them in that same folder. I still get the same messege. What should I do?