It's a constant problem for me. I'm going to try and get a refunsd because the game has been buggy and unfinished for WAY to long.
Dude, you even said your self you installed Mods... As a person who doesn;t use mods of any sort (because I am worried it will screw up the game) ever thought it might be the mod? I mean mods do things to the game that the game was not designed for thus the problem could lie in the mod and at this point uninstalling the mod may not help THAT particular save file as it may be corrupted.
IMHO Modding the game then getting upset that something doesn't work right is pretty stupid (Sorry not sorry)... YOU did something to the programing to try and make the game do something it wasn't designed to do...
That said good luck getting a refund... just a tip I wouldn't mention to steam that used mods on the game.