You have already made all the alterations I would have suggested, and if Skuzzy has already been over it with you I doubt I can improve on his advice. The only possibility I can suggest is that you are experiencing the infamous "loop error". I remember reading it's more prevalent with 256MB video cards. If you have access to another video card, try it and see if you still get the same problems with no other changes. Of course if you dont have access to another card, I dont know what to suggest. Nobody that I know of has nailed down a specific cause for the problem, other than it is related somehow to possibly faulty video cards or driver issues with certain card architechtures.