I''ve compiled and run two DirectX 7 3dImmediate mode tutorial which are triangle and texture. The texture tutorial runs fine but the triangle tutorial has a problem. Whenever I run the triangle tutorial, the monitor display freezes, I can move the mouse but when I left click, right click on anything (the start menu, other application, resizing the taskbar) or Ctrl-Alt-Del, the monitor display still freezes (there is no change to the monitor display). But it is not system hang, I can still hear the MP3 file that I open and I can still close the triangle application with Alt-F4. Does anyone know what is happening, is it surface lost as stated in the DirectX help and how do I solve this problem? Does anyone beside me have this problem too? Thanks. PS: the tutorials are located in samples\Multimedia\D3DIM\src\Tutorials\Triangle and samples\Multimedia\D3DIM\src\Tutorials\Texture