Hi Tom!
Sad to hear about your problems..
My guess is that a stable system require well balanced components, wether they're the processor, RAM, graphics card, drives...
So.. here's my FS9 PC
HP Compaq Elite 8300 CMT - running Windows 10 Home
Motherboard HP 3396
Processador Intel(R) Core(TM) i7-3770 CPU @ 3,40 GHz 3,40 GHz
... this is a 3rd Gen i7 - current generation is 11th! .. BTW, ChatGPT suggested at least a 4th Gen
RAM 8,00 GB .. ChatGPT says 16 GB would be better
Nome NVIDIA Quadro K620 (added later to my system) .. ChatGPT suggested a couple of cards priced above 600 USD so he really off here.
Resolução 1920 x 1200 x 59 hertz, 32 Bits
Both the PC and the card are from 2014 (or close to)
With this I'm able to run FS9 without problems but if you aim higher that won't do harm
If I had to buy a new PC for FS9 now, just considering FS9 (and maybe FSX) I would look for a used/reconditioned from a reliable source. Unless you don't mind paying the money for a current machine - which, for instance, may have say an i5 processor that is way better my old i7.
Not sure if it helps, but hey...!
Joao