If your having persisting problems with the client, graphics or otherwise. The first thing you should do is ALWAYS check your graphics/sound drivers are up-to-date.
ATI Catalyst website
Nvidia Driver website
Direct X
Creative Website
We do NOT recommend you use Omega drivers for your ATI card, they are beta drivers that you should use at your own risk. We do not endorse them, and are not obliged to help people who use them.
If your still having trouble, then you could have conflicting driver versions lingering on your system.
To make sure you remove all aspects we suggest the following procedure:
-Remove the drivers from the Add/Remove Programs area of the Control Panel and Windows Device manager.
-Reboot and ignore the 'Detected new hardware' prompt.
-Run the new drivers own installer and voila.
You could also use a driver cleaner if you have the software to hand.