I have had my PC for over 3 years now, i was watching some videos when all of a sudden my main monitor, that is connected to my Gainward Geforce GTX 970 GPU just went to a black screen and now all i have is my secondary monitor, that is connected to the onboard graphics. I have checked solutions online however, my GPU fans are still spinning, the DVI cable to the GPU is working. i would like to say that i installed another 8gb of DDR4 ram last week, it was all fine until two days ago.