What's the deal with my PC ?

[Osc@r]

Hey, so I've had a problem with my PC ever since I built it 3 years ago that happens periodically. Essentially, my PC freezes, my monitor is showing the last frame before my PC froze and there is an often loud but lately gentle buzzing sound (precisely like this guy at the beginning of his video : https://www.youtube.com/watch?v=24Igo_4vusA ). Nothing more happen and my PC does not shut down unless I turn off the power supply or hold the power button. When I try to turn the PC back on a few seconds after forcing shut down, the components seem to function properly (Hard drives making the same noise as usual, fans spinning, ...) but my monitor does not display anything and remain in sleeping mode, and my mouse does not light up while my keyboard light up but does not register any key I press. The problem can happen at essentially anytime (BIOS, desktop, in-game, browsing, ...), but when it happens, it's mostly while gaming, otherwise it's fine most of the time. Also, the WI-FI is often disconnected when I log back in. That is all I found was different between when everything is normal and when the problem happens. Now here's what I tried :

- Format HD and SSD
- Reinstalling Windows
- Updating Windows
- Updating drivers
- Change CPU fan
- Add RAM
- Dust the components
- Checked if anything was not plugged correctly (nope)
- Checked temperature while doing different tasks (never abnormal)
- Ran RAM test

Here are my specs :

i5 6500 3.2GHz
KFA2 1060 6 Go
MSI B150M PRO-VD (it's a Micro ATX, so the components are really close to one another, but they're not touching)
8x2 Go HyperX Fury 2133 MHz
Seagate BarraCuda 1 To
Kingston SSD AV400 120G
BeQuiet Pure Power 500W

I'm just looking for things to try at this point, because I don't know what to do.
Thanks.

[David (PassMark)]

What RAM test did you run? What were the results?
Did you try a different video card?

[Osc@r]

I used the basic Windows Memory Diagnostic and I don't remember what the results was exactly, but I checked in the event viewer once it was done and it basically found no issue. No, I don't have acces to any other graphic card unless I buy a new one (in which case I'd rather make a new complete PC).

[David (PassMark)]

The i5 6500 has a built in video card. You should be able to use that as a test. And remove the other 1060 card.

Use MemTest86 for RAM testing.

[Osc@r]

Thanks for the info, I had completely forgotten about built in video card. It did crash tho, while loading a game this time. It had the same buzzing sound but the monitor displayed strange non-linear columns of blue pixels covering about half the screen and it was not static. I'll try to use MemTest86.