I think I've encountered a true "game breaking" glitch in the form of a broken quest. The quest is from Urag gro-Shub in the College of Winterhold to find three stolen books. The first book on the list he gives you I already have, yet the game does not recognize me as having it when I go to talk to him. Yet it does recognize the book if I try to drop it or store it as it says "You cannot get rid of quest items." Huh. OK. And the kicker is every time I select the quest it keeps directing me to Valtheim Towers (where the book is located). However, I've already been there as a previous quest tasked me with killing the bandit leader at that location. I looted the area and picked up that book along the way, and I did all this before I got the stolen book quest. But now that I have the book quest I can't turn the book in and it's not even recognizing me as having it; therefore I cannot progress at all in that quest to find the remaining two books because it still doesn't count that I found the first! Grrrr...this is VERY annoying and I don't know how to fix it or even if it can be fixed.