This is getting annoying. I'm in Markath, going to do the Nchuand-Zel quest and everytime I "enter" the ruins, the game crashes to desktop.

Tried deleting my autosaves, disabled all 3 "save on ???" in settings, tried to "cheat" using the coc code, waited outside for 3 days, disabled my newer mods, and nothing worked!

I've only installed 3 new mods since my last play through (which I was able to enter these ruins no problem) and im not sure what else to do.

Is anyone else having this problem?

List the mods. I dont do PC gaming but I read enough threads like this to know they will want the mod names.

I had a similar problem with Dustman's Cairn. I wouldn't CTD but my game would immediately freeze at the load screen.
My problem was due to a bad mesh file related to Nordic dungeons.
It's an easy test. Look in your data folder under meshes/dungeons/dwemer (or similar). Copy that folder to another location then delete it from your data folder. Load up the game and see if you still crash.
If you don't, it's one of those meshes. Just slowly add them back (with correct subfolders) until you find the culprit.

If not that, the only other thing is to lookup all your mods to see if any alter that dungeon. Then it's a mater of disabling all mods and slowly enabling them until you crash.

Of course it could always be another matter entirely, but let's hope not!
Good luck.

Edit: this will probably get moved to the mods section. Also above poster is correct. Post your load order in spoiler tags in your original post.