I have a Clevo laptop. On POST the screen goes white -- not instantly, but it begins from the center of the screen as a spot and then it spreads to the entire screen.
The strange part is that in the left bottom corner I can see the start-up menu button of Windows.
I am dual-booting Windows and Linux. The strange part is that the taskbar on my Windows install has been on the top of the screen, not on the bottom, for at least 8 months now.
How is it possible from a cold boot that the GPU or RAM (or something else that I am missing) could have such information?
Besides, if I connect my laptop to an external screen, I see the POST BIOS but the laptop white screen (for some seconds) I see what I described above.
The question is not why the screen goes white, but why in the white screen appears part of the GUI from Windows -- how is that possible because you are in pre-boot sequence?