If you plan to use 3D Vision depending on the game, then you have a couple different options on how to turn it off for your 2D games:
1) Once the game loads, press Ctrl-T, and it will turn off 3D, but the drivers are on, and will cause a little bit of a slow down.
2) Go into the Nvidia control panel, and uncheck stereoscopic 3d.
For a shortcut to #2, I have a couple batch files to turn it on or off. I put them on my taskbar to easily turn it on or off, depending on my mood. Put this into a .bat file:
@echo off
"C:\Program Files (x86)\NVIDIA Corporation\3D Vision\nvstlink.exe" /enable
exit
To turn it off:
@echo off
"C:\Program Files (x86)\NVIDIA Corporation\3D Vision\nvstlink.exe" /disable
exit