Did you try replacing the CPU heatsink compound and checking the CPU fan after this work?
About 1 dollar of compound so not expensive as things go. YouTube has many videos how to do this work.
For the past month I've had a problem that may be regarding my CPU... I think. When I'm playing a graphically demanding game it will after some time make my computer crash. This has happen with three graphicly demanding games (My setup met the system specs still) and one time after I turned the computer off and on again I get this screen:
https://ibb.co/mQV355
I have two types of crashes: one where my monitor will shut off and I'll hear a fan in my computer starting to blow like crazy leaving me no choice but to turn off the on/off switch to turn the computer off, and one where (this is the type of crash that happen the most) my monitor will shut off if I play a game but this time I can still hear the game from my headphones and there have been instances where I've had a youtube video on while playing and I can still hear the video when it crashes, and my fan won't go crazy like with the other crashes. I have to press the on/off button but when I come back to my desktop the folder layout is different, I have to rewrite my password when I log in to Steam - something I normally don't have to do, almost as if my computer has "reeboted" in some way. For a time the first type of crash was the only one that happened and it would happen after about an hour if I had maxed settings and it doesn't usually happen when I lowered my settings. The second type sometimes doesn't even take more than a few minutes regardless of the graphic settings.
It's worth mentioning that I have also just had to get a new graphics card graphics card recently because my old one crashed (right before I had this issue). My PC was built in the summer of 2014. This has never happened before. I've tried cleaning the insides of my computer twice with a can of compressed air but it didn't do much. I tried with thermal paste and it didn't help. I don't know what has happened lately that have created this annoyance.
Here's how much memory and CPU my game can take up: http://imgur.com/Q4Lua7v .
My SSD is SSD 120GB Samsung 840 EVO, Basic. My CPU is Intel(R) Core(TM) i5-4670k CPU 3.40GHZ. My motherboard is an MK ASUS Z87-A ATX Z87, 1150. I've got A-Data 8 GB RAM DDR3 1600Mhz/CL9/XPG and my graphics card is GeForce GTX 780 (same as the one before). All this on a Windows 10. My case is Kab Fractal Design Define R4 Titanium Grey.
I did the GPU stress test with a program called Furmark for 12 minutes. The highest my Intel (R) HD 4600 was 80° C (https://ibb.co/gy4QBa ) and my 780 went probably up to 72° C (https://ibb.co/husdWa ). I also did the CPU Burner for about 10 minutes and my CPU went up to 82° C.Here's a picture of my computer from the left side with the cover on and two with the cover off:
https://ibb.co/g6EFwa
https://ibb.co/dTYiGa
https://ibb.co/gmqDGa
Note: Moderated edited links for breakage.

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