I have an openGL based win32 program (using glut32.dll). A few days ago, it ran well. But I got a problem yesterday. The problem is: After launching the *.exe file, the viewport does not update. When I resized the viewport, the viewport does not update either, see the attachment.

There is not any change in the code actually. I doubt it may be caused by the graphic card (NVIDIA GeoForce GTX 260 with latest driver) or...? Please help, thank you very much!