windowclass.hIcon = (HICON) LoadImage( // returns a HANDLE so we have to cast to HICON
   NULL,             // hInstance must be NULL when loading from a file
   "iconfile.ico",   // the icon file name
   IMAGE_ICON,       // specifies that the file is an icon
   0,                // width of the image (we'll specify default later on)
   0,                // height of the image
   LR_LOADFROMFILE|  // we want to load a file (as opposed to a resource)
   LR_DEFAULTSIZE|   // default metrics based on the type (IMAGE_ICON, 32x32)
   LR_SHARED         // let the system release the handle when it's no longer used
   );