I got curious yesterday and downloaded the launcher on 2 other machines I have here. Both had problems. The win10 machine is an older unit running onboard graphics, probably just barely able to run 10, at first it wanted me to setup 1024x768, as my only options, I did not do that, I had all kinds of meter studdering and wouldn't stop when clicked. One thing I did notice on both machines, it required an update when started, the win10 machine updated twice, the second update uppacked 163 different files.
The other machine is still running win7, the launcher told me win7 was no longer supported(imagine that) but that I could try and download anyway, which I did, and had problems running it also, I did not spend much time trying to trace down my problems.
I have another older(identical to the updated win10 machine that is still running win7,(this one I am typing on right now)(I can run the game on it just fine(I loaded the launcher when it first came out. I don't know if the current launcher is different then the original(my advice is to not screw around with it, if you have/had the original launcher loaded). The only difference between this machine and the upgraded 10 machine, is there is a GPU in this one.
I saw a post yesterday with someone else's machine specs, they were running an AMD display card(GPU), it is a $70.00 low end card running passive cooling(no fan), that could be the problem with that machine. He was also running an Intel I3 CPU.
You asked, it ran yesterday but not today. I have to replace gaming GPU's at times in my gaming rig, due to the fact of changing technology. As game performance increases so do the graphics, making an older GPU card obsolete. So there is the answer to your question. Not saying that is the case here, but all new games(this is one after all) come with both minimum and required specs. In most cases, if you don't reach minimum specs. the game doesn't run.
For those having problems, try runninng a lower display resolution, I have seen it work in the past with games. Some areas of games have a lot going on graphic wise and higher resolutions just won't work correctly. Another big factor is how much ram your computer has, especially with onboard or CPU graphics. Graphics card have their own ram.
There are 3 different types of graphics, a graphics card(best)(providing it it not a low end card), graphics on the CPU, and graphics onboard the motherboard.
Sorry for making this so long, hope all that are having problems read all of it and maybe something I have written helps you.
Gary