Check CCC for anything the driver update may have changed, particularly any settings related to driver based AA.
Did you make any other changes to your system? Are there any third party utilities like MSI Afterburner and Fraps running in the background?
Just got Ragnarok Online 2 installed and the aliasing is terrible. So I downloaded FxaaTool, SweetFX and attempted using nVidia's own tools.
The game CTDs about one-two seconds after launch and I never get in if I use FxaaTool or SweetFX (or if the active profile files are in the game directory). If I use nVidia's configuration tools, the game looks great but I cannot use ANY of the ingame overlays like shadows without getting a blue box taking over half of my screen.
There should be a file called "log.log" in your game folder. Post its contents here.