That's a pretty old PC and dated parts. Many look to be 4 years old. Let's also find out if you are keeping the insides of the PC clean as well as a fan check. Do all the fans operate like new?

-> Another problem you run into is that as the boards age, they tend to get less reliable. I've seen this build on the counter too many times and you can only fix it with new boards (motherboard, GPU, etc.)

Let's get a WEB SPECCY report in case more can be found: Read how at
https://www.piriform.com/docs/speccy/using-speccy/publishing-a-speccy-profile-to-the-web