Here it goes again...crash to desktop

[Curmudgen]

For several weeks, after using full screen mode this had not happened. This event started again several days ago and has been persistently occuring once every play session. Invariably it also occurs upon initiating combat.

I crash all the way to desktop, and have to completely relog back into the game.

Any ideas? This had been happening with windows mode, but since full screen mode change for a long time it had not happened.