So this was an ongoing problem in Chapters 1 & 2, but mainly in the two inns. Crashes elsewhere were very rare.

But when I went to chapter 3, it became a very regular thing, no matter where I went. So I did some research, and found some suggested solutions. The one that worked, partially, was putting the game into Windowed mode. The crashes became less frequent, to the point where I could get maybe 20-30 minutes of play before one hit. Not great, but it was progress.

Now I'm at the Posh Party and it's just an unholy nightmare. I can't get more than 2-3 minutes into it before instant CTD.

And there's no proper error message. Just a notice that the game has done something naughty and Windows needs to kill it. I can't get it to give up any details on what this error actually is.

I am running mods, but only a handful, and all ones I've always run (FCR, Scabbard Mod, Hi Res Textures, HI Res Character models, Inferno UI, and some bug fixes for certain quests). I've re-verified the game. Doesn't help. I've stripped out everything but FCR. That doesn't help.

The only common thread I've noticed is that there's this weird screen effect where it kind if shimmers, like with Cat potion, just around the outer edges. I know that's something FCR made into a feature rather than the potion, so I get the feeling that's the culprit, but I can't just remove FCR without breaking my game, and i'm too far in to start over. I'll be honest, I hate the gameplay, and FCR is the only thing that makes it tolerable. But I want to replay all the games before finally sitting down with Witcher 3. If I can't find a solution, i'm just going to have to ditch TWEE and move onto 2, and make do with Gopher's Let's Play series.

System Specs
Core i5-6600K
16GB RAM
Geforce GTX 1070 8GB
500GB SSD + 2TB HD.

I don't use any mods and the crashes I experimented were not as frequent, but around that time in the game I found out that deleting old savefiles helped a lot with preventing crashes. Just in case this (very simple) solution is not among the ones you've already tried. Someone else with more technical knowledge will probably have more ideas.

I have the feeling that the game is the reason my PC restarts by itself repeatedly... But I am not sure. I cannot prove it but my PC never restarted in the past.

I finally got it "fixed", but I don't know how.

I re-verified the files, and reinstalled my mods again, only this time I left out the High Res Texture Pack and High Res Character Models.

My game is now MUCH more stable. It crashed twice since, both in the New Narakort, but aside from that, it's been far smoother. Don't now what changed, but I'm finally in Chapter 4.