Hello again Peter,
Thank you for your replies and information.
After doing all ofthe above, except the "steamfix" part (the reasons are as follows: 1. the program is something I'd rather not trust after it sent some data about "bugs" without prompting me and 2. SH3 ran well from Steam folder before anyway) I decided to do the Nvidia part, but what I see is different than what's in your tutorial.
Here's the link:
http://i.imgur.com/k9mudJ4.jpg
I've changed the scaling to 100%, didn't seem to work however. I reckon it's something to do with video settings. I'll post a reply after I fiddle with it some more.
Also, just to clarify, the game runs in the menu and loads the mission, but crashes about 10% from fully loading the mission.
If I run out of options I guess I'll have to do the steamfix. However, I'd like to exhaust every other option first.
----
After fiddling with whatever simple settings SH3 has in Video, the game still crashes, but loads the mission much faster when most video options are turned off. Crashes at roughly the same spot, even in windowed mode.
After moving SH3 outside of steam folder into C:\ and renaming it "SH3" the game runs just as well as in steam folder, still crashes at the same spot.
Deleting the folder in Documents also did not work.
Doing a fresh re-install on steam again. Going to verify the files after it downloads.
I've also noticed that after update I have this program:
http://i.imgur.com/t9oE6Zg.jpg
----
Okay, it loads, but now I have this problem:
http://www.subsim.com/radioroom/showthread.php?t=221324
-----
Solved! Checked the intergrity of the game cache, no files were downloaded, but after I did that the game started functioning properly.