XP64 / DX9 black screen

This might possibly do better in a another section but I'll try here first.

Has anyone else had any issues with DirectX9 on a new install of Windows64bit?

I'm using an Nvidia 6800NU (385/895) DX8 games work fine (LFS) and OpenGL games (Q3 & Q4), but DX9 generation games fail.

e.g. #1 - UT2004. Loads up, realtime 3D logo intro plays VERY slowly, main menu is just black screen. Sounds are there (rolling mouse down menu) but it's a blank screen.

e.g. #2 - Hitman Blood Money Demo. Nvidia sponsorship video plays sound only, black screen again from then on.

e.g. #3 - Condemned. Intro videos play sound only. Main menu is black but cursor is visible.

e.g. #4 - 3DMark06. Get horrible screen flicker of windows desktop when about to display first benchmark's loading screen. Then get error and benchmark aborts.

Some of these problems seem to be related to codecs I've heard, but it appears to be more of a DirectX9 issue. I've tried the latest Nvidia driver and the Forceware beta, with no change. I gave up when Windows said I had significantly changed my hardware and should reactivate, no hardware has physically changed since this reinstall.

What can I try next?

Bump

This happened so straight away that I hoped someone else had encountered it!

dxdiag is fine DX9c is installed, but DX9 games produce no video.

All resolved.

It turns out the latest two drivers from nvidia are not compatible with my setup - Asrock 939 dual, GF6800NU, XP64.

Have to get by on 78.03 drivers. Wierd

i had exactly the same problem a few months back same way to resovle as yourself
but my setup is an asus mobo (sig) so maybe its a asus/asrock problem

This fixed it for me cyclo : link

But AGP bus speed may now not be set right and in intensive games (HL2:EP1 with AA and HDR) fps dies to <4fps. Can't win still fixing this.