I do not know how you make such assumption especially faulty motherboard.
If faulty motherboard or PSU, the PC won't be able to turn on.
TS issue is it will random freeze which is mostly RAM or Windows issue
which many have advice him to do so but he seems don't bother to do anything about it
except complaining.
1. Faulty Storage drive - Windows won't be able to boot or BSOD when loading.
2. Faulty GPU - Screen artifacts or no display but TS PC can turn on and play games.
7. Faulty mobo - It is able to turn on.
8. Faulty RAM (unlikely since already tried with 2nd RAM unless both RAM specs not supported by mobo)
KLEV ram are supported by most motherboard and are sold locally.
There are China OEM RAM which I saw before, those will have compatibly issue but not KLEV.
PS I hope you are not a repair shop posting here hoping for someone to approach you.
If so, I hope no one patron you since not only you did not read through the thread
but clearly lack experience especially listing so much faulty part than might as well as say PC is spoilt.
Firstly have to see how old the PC is, RAM over time will have issue
thus this should be the first thing to troubleshoot and run test like Memtest.
Unless the PC PSU blown than yes many parts could be faulty but what was the issue in this case?