I just can suggests these:
1) Use latest graphics driver. But I recommended using stable driver. This is usually few versions down from the latest.
2) If problem persists, try adjusting graphics acceleration settings in windows. This is can be found on display properties.
3) If you have another graphics card, try to swap with it.
4) Are your graphics card overclocked?
5) Try using different resolutions, e.g. 800x600 for most standard tests.
6) Is this problem appear in another game?
In reality, doesn't matter who's
right but most important is who's
left.