Computer Goes Black (Not a Monitor issue)

I had an issue like this before and it turned out to be the HDMI cable, check your cable when the screen next goes black by pulling out the cable and then putting it back, then turn the monitor of and restart to see if works...sorry I cant help more but my fix was a new HDMI cable. Also do a clean reinstall of your GPU driver. MAke sure you remove the old driver and let windows do the basic GPU driver instal and see what happens.

I've been chasing the solution to the same problem - mine goes black unpredictably, and the symptoms have morphed - initially it would boot to a black screen after showing the POST screen (my system is below, also with a Nvidia GPU). But the fact that even then i'd get a "no signal" msg after the computer was loading windows, indicated it was not the display. I've chased a number of solutions on the web and have not found the solution - the hdmi cable suggestion above is the first thing i'd try

I actually moved my GPU to another computer and it gave me a black screen one time, and then after a reboot, it played "nice" for 3 weeks steady with no black screen, so i moved it back to my main rig and within 2 hours had gone black. Mine now does it unpredictably, maybe while i'm rendering a video, which isn't that heavy a load on the GPU, or while browsing, and oddly will go black when i clik on a web link, like a search result in amazon - and then when i reboot and go back to that same search result and clik on it, it will do it again, the instant i clik on it

one suggestion, google for and download "WhoCrashed" - on some of my black screen, it will report the error event, usually showing "memory management" or a kernal in the nvidia driver error?? But at least it gave me a lead to follow. There's a thread on the GeForce forums on this subject, you might take a look at, after checking the HDMI cable, and note they're claiming the last few drivers from Nvidia have been buggy, and they identify the last known stable driver: https://forums.geforce.com/default/topic/1035287/nvlddmkm-sys-crashing/?offset=1

note on the nvidia web, all the Nvidia GPUs seem to have used the same drivers, so the driver the mod recommends in that thread should be viable.

right now, as it had demonstrated the black screen one time on the alternate computer, i sent it in to zotac for inspection - and they just emailed yesterday that no issues were found with it, so they're sending it back. I didn't find the above thread on the GeForce forum. When my gpu gets here, i'll be trying that, fingers crossed

hope that helps some