When you run a graphically intensive program in full screen mode, your monitor flickers or is unsteady?
If the program uses DirectX, and you have DirectX 8.x installed, and the program fails to set a redraw rate, you may experience this behavior, because a redraw rate of 60 Hz may be used.
NOTE: To determine the version of DirectX installed on your computer:
1. Start / Run / Dxdiag / OK.
2. If you receive a request to check for digital signatures, respond Yes (or No).
3. Select the System tab.
4. The DirectX version is listed at the bottom of the System Information section.
To resolve this issue, upgrade to DirectX 9.0.