Eek... I'm sorry no one answered this question. I was sure I responded to it when you first posted to tell you that your video card was probably the problem, but apparently I didn't. I'm really sorry.
Are you a Season 1 customer or did you just buy episode 1? A change has been made to how the auto saves work starting with episode 3 that could possibly fix the problem you're having, but you'd have to unlock the full episode to find out. Please email
support@telltalegames.com and reference this thread and I'll get you set up.