Video Corruption with ATI X1300 XT & Games

I'm using an ATI X1300 graphics card with 2 flatpanel monitors.  When I run games, such as Civilization IV, I get various types of corruption on the screen.  There are triangular areas that flicker.  There are small rectangular areas that are missing or at least the wrong color.  There are stray lines shooting off in various directions. Etc.

I'm using DirectX 9.0c and have installed the latest driver from ATI. 

When I run the Direct3D tests in DxDiag, I see similar types of corruption.  Specifically, during the test there is a cube spinning on the screen.  Half of each face of the cube is missing.  I believe that if I can get the Direct3D test to work correctly, my gaming issues will also be solved.

Has anyone had a similar problem and does anyone have any ideas about how to resolve this issue?