I have a big problem....a few days ago, I installed a new ATI Catalyst 6.6, the Control Center version. After that, my video card got all messed up.

I'm using Pentium 4 1.8GHz (@2.5GHz), Sapphire Radeon 9600XT(256MB), 512MB RAM, Windows XP Professional (without any service packs, but updated regulary), all that on ASUS P4P800-E Deluxe. I have all new drivers installed, DirectX 9.0c and new motherboard BIOS.

When I start ATI Control Center, first this warning comes up saying: "CLI Application has encountered a problem and needs to close:" Still, I somehow manage to work in ATI CC, ignoring this warning. When I enter the SMARTGART section, the AGP speed is set to OFF(0X), and before, it was always on 8X. Also, the FastWrite, AGP write, AGP read, PCI write and PCI read are all set to OFF. If I set those to ON (as they usualy were set), the RETEST option also turns on, so when the computer restarts, it retests the GPU and sets the settings back to OFF.

I looked at the DirectX Diagnostic tool; it seems to be all OK there, no problems in "DirectX Files", but in DISPLAY section, DirectDraw, Direct3D and AGP Texture Acceleration are "Not available", before, those were always available and enabled. Now I can only test DirectDraw, but the Direct3D Test is not available.

I've tried reinstalling GPU drivers, reinstalled DirectX, installed new motherboard BIOS....I just can't fix it. It's as if my motherboard/GPU don't even support AGP 8X or Direct3D...and I know they definitly do!

I've installed DriverCleaner. I managed to clean all the ATI components, and reinstalled the driver again. Now all the Windows animations work fine (they were all choppy and in low FPS), DirectDraw and Direct3D are now enabled and working normaly in DxDiag, but the AGP Acceleration is still "not available". Also, in ATI CC, the AGP speed is still set to 0X. The games are practicly unplayable.

I used SANDRA diagnostic software...it confirms that both my motherboard and GPU support AGP 8X Speed, but alerts me that it is not enabled. I can't find anything in BIOS to set the AGP speed.

So, anyone, HELP!!!

I would try this:
completely uninstall your ati drivers... even with drivercleaner --there MAY be miniscule bits/pieces of the drivers lurking in dark corners of your registry. AFTER uninstalling + running drivercleaner-- open regedit... look under HKLM/software-- look for ATI, or Catalyst folders ...right-click and delete. Do the same under HKEY "current user" -- you might even look under HKey root. You might also run a registry-cleaner afterwards-- sometimes they find the less-obvious keys.
Once you are as sure as you can possibly be that it's all gone -- reboot.
then download A FRESH COPY of the driver install file. In your case I might consider reverting to the previous version (6.5)

DISABLE your antivirus software-- they can interfere with low-level driver installs-- like video cards.
you could also run MSconfig and do the clean install...

click on selective startup/ services/check the hide all microsoft services checkbox/ select disable all
click on the startup tab-- click disable all. reboot again.

find your new copy of the install file and run it. when prompted to reboot you can click no... and go back into msconfig and reverse the previous steps... or to be EXTRA cautious -- you can reboot once... THEN re-enable everything and reboot again.

Let us know if this helps.

I haven't had an ATI card for a while, but when I had my x800, a certain range of drivers wouldn't let me use the CC, which was a fairly wide spread issue. This is a little over a year and a half ago.

Try a different version driver if you already haven't.

A good source for video card drivers is www.guru3d.com
they have beta, and WHQL Certified.

I've managed to solve the problem...not the most unpanefull way but still....I've reinstaled Windows and everything works great now...

Thanks anyways!

Some folks actually plan to reinstall windows every 3-4 months or so because they believe it degrades in performance no matter what you do.

I find this a little extreme,myself... I detest reinstalls-- so I try harder to keep it in shape. with XP I've gone several years ...before something got corrupted beyond repair.