When I launch FF4, I see a white windows frame for 2-4 sec before it actually show the interface inside the frame. This is not happening if I uncheck the "Use hardware acceleration" checkbox. However, I would like to use it... My System is a new Dell XPS14 with a Intel core i5 (integrated HD graphic + Nvidia Geforce M420). My windows 7 x64 is fully patched, and I just upgraded both of the graphic drivers... Any other ideas?