Let's not jump to conclusions yet, it might not be DirectX that's causing the problem. DirectX is closely tied into gaming applications and since Noob mentioned nothing about gaming problems, let's keep it simple and try focus the problem shooting to 1, 2 areas.
The first thing I would try is using XP's system restore. Like i said earlier, this option will work only if you have a valid restore point you can revert back to BEFORE your problems began.
Otherwise, you can go through the control panel and open your 'Add/Remove Programs' applet. If it lists the update pack you downloaded from MS's website, try to uninstall it.
You can access the Device Manager through the console management feature. Start | Run type in "gpedit.msc" w/out the quotes and you'll get the group editor policy. In the top drop down menu, you'll see an option to access the Device Manager there somewhere. Can't reme3mber the exact menu option right now.
However, i have an easier method of uninstalling your video card driver. Try booting into safe mode to uninstall the driver. Reboot the system normally and your system will say Found new hardware... when it prompts you to install the driver, you can insert your CD, or just point to the path where it's stored.
The other problem you have (perhaps unrelated) is your device manager appearing and disappearing when you click on it. That's strange. It might be a virus problem and it might not be. Again, i hate to jump to conclusion. Do you regularly update your virus definitions? Have you run Spybot or AdAware to check for any malicious spyware?
