You see with mine once the blank screen occured (which was the instant the game/benchmark loaded) you could not simply alt-tab out of it as the machine needed a reboot... and then it would usually not POST for 3-4 times before starting again and repeat.
The fact that you can alt-tab out of it suggests it may be something else in your system causing it.. I take it you have run everything at stock to see if it still happens.
At first, i just uninstalled nvidia drivers, safe mode /driversweep ect, then installed AMD 10.12, then all my problems started,
so i then done a fresh install with just drivers and a few games/benchmark progs to test, and same things still happen, games freezes, all this was done while system was a stock settings ., no overclock on CPU or GPU
send back to OCUK, they run various benchmarks and say its OK, so i now have it back !