This has been reported before, almost always with the new nVidia drivers. Usually, you have to back the new driver out and go
back to the old driver.
Also, you might want to check and make sure DirectX is working properly. Run dxdiag.exe from Run command line. Take a look at
the resolution your monitor is running at. At high resolution, the stars are dim to begin with, and since each star is a
single pixel ... you might want to lower your resolution, just to try.
Anyone have anything else to add?