This should be a driver problem, so this driver should not be used any more. (May be a compatibility issue)
If you install the system, go? Official website downloads the latest driver of win7.
Or go directly to NV official website (plus three w) NVIDIA.cn/page/home.html. 。
Is the driver download page downloaded from the win7 driver of the graphics card below 9800GT?
If not, try something like this.