[John Rogers]

I would say the video card in the laptop, probably built it is over heating possibly? Right click on an open area of the screen and see what sort of video system you are running and what resolution is. Sometimes this happens if drivers have not been updated as I am guilty of doing and my screen will revert to 1080p when I log in and I have to bring up the utility of the video card to jump back up to 4k resolution. There will then be a little window saying new drivers are available soooooo I get the but that always forces a reboot.
John