I've made it to the end of the game, but whenever I try to take the elevator down to the bottom of The Master's lair, the game crashes. I looked up several sollutions online, but none have worked so far.

My specs...

Windows 7 Professional (64-bit, SP-1)
Intel Core i5-4590 @ 3.30GHz
16GB RAM
AMD Radeon R9 200 Series

Any piece of advice is apreciated!

Played it once on a modern system with Wi7, i used
Fanpatch 1.2
MariposaFix
Settings Win 98, 256 Colours&low ress

I don't remember if it was the the Fanpatch or the Mariposafix but one of them was incompatible with old saves.
Hope it helps

I tried Fallout Fixt, but that was incompatible with the old saves. Can you tell me where can I find the mods you used?

Tried the old links i marked the last time i playd but there all dead.
Searching for newer replacements i found

http://www.nma-fallout.com/resources/categories/fallout-1.2/

http://fallout-files.de/index.php

http://falloutmods.wikia.com/wiki/Main_Page

All three have patches, fanpatches and mods. I hope you find something that help.
Take into mind...i didn't test any of these, so i don't know if they work.

Thank you very much for your help!