Jake,

Don't know if you've found a solution to this problem and interestingly
enough no one else has reported a real solution either. I have a 9550 card
too and what finally worked for me were the drivers from 2004 that came with
the card's driver disk info follows:

Ati Technologies Inc.
7/10/2004
6.14.10.6458

These are digitally signed and remove the error 43 code. Also speeds up
Vista a bit.

Hope this works for you too!

Mike

"Jake" wrote:

Interestingly, I attempted to install a WDDM driver for a Radeon 9500 (not
9550). I rebooted, and Vista again reported code 43, just like the WDDM
driver for the Radeon 9550. Even a wrong driver acts like the correct driver
does.

However, Vista does correctly recognise that the video card as a Radeon
9550. It just always thinks the card has reported a problem.

The XP drivers work fine, so I don't think the AGP drivers could be the
problem. The video card drivers seem to work fine for others, so I don't
think the problem could lie with the WDDM drivers. So I am not quite sure
what is causing this error.

It would be very interesting to see if anyone finds a solution.

Jake.