My game crashes on npc quest

Right now i cant do any of my job quest or any quest that involves a cut scene. Every time i try, it does cut away and go through most of the scene. Right before the scene ends and im to get the quest the game locks up on me. My chat still works and i am in the game, but im just staring at the npc with nothing in there dialog box. All other quest giving npcs work fine as long as it dont involve a cut scene. I have already reinstalled the game and still no luck, my computer is pluged in directly to my router so its not my connection. Can anyone help me, please?