Trying to fix my computer

I posted a question about a PSU earlier and this is a follow-up to that post: https://pchelpforum.net/t/help-finding-a-psu.50321/#post-91880

Unfortunately, it didn't end up working and the problem persisted, so I returned the new PSU and reinstalled my old one.

I recently ran some tests for my Western Digital HDD and both the short and extended tests passed.

I ran memtest86 for my RAM and they passed those tests.

I've done Furmark tests on my GPU and it got through them just fine.

Now I want to try to switch out the CPU and the MB, which I've heard is best to replace both together. I wanted to get some opinions on what to get and a bit of a walkthrough on how to replace them. At this point if replacing these don't work, I either need to get a new computer or check all my connections and cords to see if there is any damage I missed when looking at it previously.

Here's my current speccy if this helps: http://speccy.piriform.com/results/4boqr6WhW6tmHKmbOF4L5Yf

To Bruce: I use it as a gaming PC. I play games from all levels of graphical levels, Half Life to Witcher 3 Wild Hunt. I eventually want to be able to use CAD or other engineering softwares.

To Evan Omo: It is always a hard freeze. More recently, as in the last few months, I have been getting a blue screen. Something that has happened only a handful of times is an automatic restart. My screen goes black as if I just hit the reset button. I am on my third HDD with this computer. My first one was one I brought over from a previous PC that a friend built for me. That one lasted two and a half years with only the same automatic restarting problem in the last few months. After the transfer, things didn't start freezing until I plugged in the second monitor to the GPU, I was using the HDMI and DVI at the same time, where the screens would go blank but if I was watching a video, it would continue playing the sound. After a few months of that, the freezing started.

There are certain programs that I've found that make it freeze more often, specifically Tabletop Simulator and Age of Empire Definitive Edition. With the latter, it happens within ten minutes of me starting the game. Sometimes it freezes while I watch Youtube videos, and others it's idle. Either on the desktop or the login screen. It has frequently happened overnight for me.

This is true even if I already have an above average graphics card and RAM?

Okay, I wasn't sure if it had that listed in the speccy.

I guess the main question I'm asking is how likely would replacing my CPU and MB be in fixing my computer of the problems it's having?

Okay, I certainly hope it's not the GPU.

Would there be a type of MB architecture that you'd recommend for gaming? Or somewhere I could find good guides on the different types of architecture available?

I'll have to do some research on the subject.

Thanks for answering some basic questions for me. I won't be able to get the components in time to reply to this thread in a timely manner, so you can close down the discussion.