With some older games, I've noticed I have occasionally some graphical abnormalities or flickering when I've got my graphics settings with FSAA or ANISO enabled.
With my nVidia/Quadro card here, I go into Display from Control Panel, then select the Settings tab and pick Advanced, then there is a tab for my graphics card with an nVidia logo by it. Once I'm here, I can pick "Performance & Quality Settings" and I then make sure antialiasing and anisotropic filtering is set to "Application controlled". You might also want to enable/override Vertical Sync (to ON).
I'm guessing here, but that's what I've experienced.
Other than that I can only offer the usual "update your graphics drivers", sorry.