This might help.
Install DX9.0 from the microsoft server.
Install the newest drivers from s-seven.net
(Be advised that I am not certain if you can use these drivers with the 128M9 - they should work because the hardware is essentially the same)
Look around to find drivers for ATI cards that use 128MB of DDR. But try the s-seven.net 6292 or the 6255 drivers. Try both and see which gives you the desired results.
This should make things work.
But oh - make sure you go to the ATI control panel (after installing drivers) and switch off "Wait for Vertical Sync" and reduce the detail levels in OpenGL and Direct3D to "Quality".
Let me know if this works...
Best of luck