Been watching your temps?
64C max for gpu, cpu in the 40s to maybe 51C, should be fine.
PSU up to snuff?
HX620W Corsair been fine until now, even when the OC was higher.
Have any WU failed?
Haven't had 14.4 long enough to finish one.
Is your PC set to automatically re-start after an error (Right Click Computer>Properties>Advanced System Settings>Startup and Recovery>Settings>Automatically Restart)? If you uncheck that box it should spit out an error message and not restart, so if it's a BSOD or something you'll get a chance to see the STOP code, or other error message.
Yes, it does restart automatically, but if there is a BSOD it should show it for a couple seconds and then restart, I was sitting at my PC when it did it once, and it had NO BSOD. Also, if it blue screens it restarts and you see either your POST or mobo splash screen and this didn't... Its like Windows reset, but the PC didn't.
All your questions are things I've found others struggle with online looking for a solution, but the thing is, temps and psu are unchanged, so the only thing I can think of is the 14.4 update.
Roll back your driver, see if that causes the problem to stop.
I hate driver updates if there is no problem, why fix it. But I also hate my PC telling me things are out of date, so I tend to keep up with it. I am fine with going back, but a newer version should not be less stable.
The PC has been folding for 14 hours straight now and no reset. I lowered my gpu from 1050 to 1025 and that seems to have been it, but I shouldn't have to since it used to be folding stable at 1070 for weeks! I only went to 1060, then 1050 because I would get artifacts in a couple games.