Question Computer displays red lines and crashes, need help diagnosing the issue

[HippasusBabe]

Hello everyone!
First of all, I'm not sure if this belongs under "system", please let me know if it's in the wrong place.

I'm going to try to keep the post concise and precise, also English is not my first language so apologies in advance for possible mistakes.

First off, my specs:
Msi 970 Gaming Am3+ bought october 2017
amd fx 8350 processor, about late 2017
Sapphire AMD Radeon HD 7950 Boost 3GB GDDR5 bought Sept 2014
ssd 250gb Samsung 850 Evo Sata3 bought january 2018
psu: Corsair Cx750m 750w bought november 2017
I've built this rig myself, updated a few parts, and I've had it in its current configuration for about 2 or 3 years, without any issues.

Next, the problem:
A few days ago the computer started to crash into a weird coloured screen:

https://imgur.com/a/94Z8kp5

View: https://imgur.com/a/94Z8kp5
(as you can see, happens with 1 or 2 monitors).
After this I had to reboot the computer manually, and after rebooting two red lines appeared on both monitors:

https://imgur.com/a/Ac0lPD6

View: https://imgur.com/a/Ac0lPD6

With these lines I'm never able to access OS, it gives a BSOD informing of a failure loading Windows and I have to reboot (I haven't been able to replicate it so I could take pictures, and I don't want to keep trying and risk damaging -if not already damaged- hardware) until eventually it just loads up normally without lines.
This problem happens with very small workload on the pc. First it was with some not too gpu hungry games (KSP, Rocket League), then it started to heavily stutter on tasks as simple as browsers, and sometimes it just goes to those coloured screens if I try to run some process while windows is still booting.

Finally, things I've tried:
I've reset BIOS settings. Important note: The computer froze INSIDE the bios once.
I've jumped the CMOS on the board back to factory defaults.
I've taken out and placed back most components.
I've monitored all temps with MSI afterburner, Fanspeed and some other programs which names I don't remember. Temps are fine. It crashes with nothing over 60°C.
I'm thinking maybe something related with voltages perhaps, but don't know what part could be the one failing, not sure how to check if its PSU either. I have not OCed CPU, GPU or anything for the past few years.

Thanks in advance for any help!!

 

[scout_03]

list all parts of system and age they have for psu use occt to stress test about 10 min and take note of voltages before and on test you could also use hwinfo sensor page to see temp with fans speed ad voltages in test if you could have the gpu test in another system .

 

[HippasusBabe]

list all parts of system and age they have for psu use occt to stress test about 10 min and take note of voltages before and on test you could also use hwinfo sensor page to see temp with fans speed ad voltages in test if you could have the gpu test in another system .

Thanks! I've tried running it. At first it said everything was ok. I started the test and it went fine for about 4-5 minutes until it suddenly crashed. Now I've got the 2 red lines again and it takes a few resets to get it to boot up, so I haven't tried again. The voltages looked normal too. The problem is that when it crashes I have to reboot it a bunch of times until it eventually and randomly boots up without the red lines and gets into windows. Otherwise it just freezes black before getting to Windows or gives me the BSOD.

 

[HippasusBabe]

list all parts of system and age

I've edited that on the original post, at least what I could find info on. Rams are a couple of months old.