System:
Intel i5-3570k
Gigabyte GTX 770 Windforce (2GB of VRAM)

8GB of RAM

850 Watt Powersupply

2TB HDD
Windows 10

I have 21 hours of gameplay since launch. The first 15-16 hours of it were plagued by crashes that seemed like PSU failures, but switching PSUs did nothing. It has since been fixed by clean installing windows 10.

Just two days ago I get in a good 5-6 hours of uninterrupted play followed by a crash that restarts my PC. I decide it's not a big deal and go to sleep after shutting down the PC. The next morning I am able to boot up my Fallout 4 and get to the main menu. This is where it begins to go downhill for me. I click "Continue Game" and it flashes the green loading symbol in the bottom left hand corner of my screen, and then instantly closes itself. I'm looking at my desktop without any errors like "Fallout4.exe has stopped responding". Steam shows me having stopped playing my game and I'm back to being "Online" as opposed to "In-Game".
I was wondering if it was possibly a problem with my save file, so I reboot Fallout and choose "New Game". I'm able to view the entire opening scene but upon seeing my character in the mirror, my entire PC blackscreens and restarts itself. This has been tried with both of my PSUs (One of them was taken from another build that 100% runs Fallout 4 fine).

I've looked through various forums and help threads without finding anything exactly like what I'm experiencing. I've tried verifying game cache on steam (All files successfully validated), clean installing Fallout 4 (and once against verifying game cache after that failed to fix it, still no problems), uninstalling and reinstalling Nvidia drivers, disabling Nvidia streaming to Shield Tablets, Running it windowed, windowed borderless, various quality settings, various resolutions windowed, various resolutions fullscreen. Programs previously installed on my PC are minimal since I just formatted my HDD to clean install windows (only being Steam, Chrome, Nvidia Control Panel, Curse Voice, and VLC Media Player), Anti-Virus shows nothing (Malwarebytes, Defender and MSE), I've ended all background programs that were unnecessary and tried it as well, no dice. Other games still run fine since my OS clean install.

Temperatures on my CPU (with load) are around 25-30c (water cooled) and on my GPU are 35-40c under load.

Any other information that you need, just let me know. Any insight at all is welcome, a permanent fix would be amazing!

Edit: I don't think there were any posts similar to this here, if there are please link me and I can close this thread down