I a fullscreen windows graphics application, does the size you set it CreateWindow matter? I thought that the only really important thing was the display mode you set in for example DirectDraw.

nope, the window size does not matter, but i find it best to use GetSystemMetrics(SM_CXSCREEN) and GetSystemMetrics(SM_CYSCREEN) so the window is full screen anyway before you set the display mode, which takes a couple of seconds

If you use a fullscreen application with DirectDraw (or something like that) be sure that there is no taskbar... because the users mouse input will be applied to the taskbar if it exists.

Greetings Dark