Weird I'm having a very similar problem. It started when I was getting my Hotas configured in Dcs for the F18c I just purchased, I was in the controls page when my screen all of a sudden went black, with a message on the screen No video output, pc is still on, the only thing I could do is a hard reboot(I hate doing that), once rebooted I updated the video card driver , things seemed fine, went back to Dcs but I had no sound, got out and the screen went black again, no video output. From the testing I could do, it's only when I got into Dcs that this would happen. Now the pc reboots all the time, no time to diagnose anything
A recent built with a 500w EVGA psu
Marc..