I've got the same problem with my Radeon 9600 and haven't figured it out yet.
I haven't got a clue what might cause the picture to flicker and fill with errors.
Some help would be nice...

My old Ati Rage 128 works fine with this motherboard... and 9600 works on other computer.

What is the exact problem?

Is this a new problem? Were things working OK previously? Any new hardware and or software?

In changing drivers have you deleted all the old ones?

What is the make and model of the motherboard?

Does it support the Graphics Card?

e.g. AGP 2X _ 4X _ 8X ?