That's good news. ?
So if the backlight was stil on and you are not using an HDD and there was no USB-Device.
And with the reinstalling in mind.
It was an corrupted Windows installation or just a normal Virus.
But if it comes back you can reinstall windows with an Image of Win 10 1809 you can download it with the Microsoft Tool and make sure you have your serial just in case.
If it still comes back you have to test your hardware like SD-Ram, SSD and if it's possible GPU.
Greetings Thorscript