In either case, the unfit Windows 10 screen won’t show in full screen and display is not filling the screen on Windows 10.
Normally, a PC screen not fitting the monitor can appear right after you upgraded the system to Windows 10 or when you connect your computer with another monitor. That means Windows 10 won’t fit the screen. Sometimes, your computer suddenly turns black for a while when you are watching videos with either smaller or larger text.
It is a common phenomenon that suddenly Windows 10 screen seems strange when compared with what it was before.
