Try to install game one more time, like nothing happened, THEN uninstall expansion pack, first (don't delete any files yourself), and the game, next.
I've tried that. It was probably my fifth time trying to uninstall the game before I noticed that the files were still there, and that's when I deleted them. Though your right, it is my fault that the game is messed up because my problems began when I accidentally moved some files, but when I went to move them back it wouldn't work.
Also what do you mean by "try to install game one more time"? Part of my problem is that I can't do that.
Sorry if I was unclear before, I appreciate the help.