Blender crashes frequently when rendering if the blender window is on display 2 of a dual head setup, but not on display 1.

Had problems with blender crashing on rendering animations. Downloaded latest Nvidia drivers (Driver date 11 Nov 2005) and reinstalled. Still crashes after 20 or so frames. While messing about I switched my display setup so that blender ran on the "other" screen of the dual head card. Blender did not crash. I have repeated the test as follows.

1. Load blender (move belnder window to display 1 or 2, vary full screen / restore size).
2. Open last file
3. Press "Anim" button.

Monitor 1, Full screen, rendering OK
Monitor 2, Full screen, rendering crashes apparently always
Monitor 1, Not full screen, rendering OK
Monitor 2, Not full screen, rendering crashes apparently always

I have a PentiumD 2.8G 2Gb RAM, Gigabyte Nvidia 6800 and 2 x HP 1740 displays. Win XP Pro. Blender 2.37a