3d Model Problem in Archicad

I am having problems with 3D model in OpenGL - Archicad Version 9. I just upgraded my graphics card to BFG GeForce 9800 GT OC 1gb. The model looks and moves great while navigating, but image disappears when static. I installed the latest Vista 64 bit drivers with no improvement. Thanks for any help you can provide.

Dell Studio 540, Intel core 2 Quad Q8200,2.33 GHz 6 GB, Vista Home Premium 64 bit, BFG GeForce 9800 GT OC 1gb

could be anything. you should ask the developers/support of Archicad instead.